LQMS Sample Transport & Quality Control Guidelines PDF

5-6: Sample transport Managing sample Ensure that all regulations and requirements are met when transporting samples; transport be aware of any national requirements that apply to samples transported by hospital or laboratory vehicles....

5-6: Sample transport Managing sample Ensure that all regulations and requirements are met when transporting samples; transport be aware of any national requirements that apply to samples transported by hospital or laboratory vehicles. All personnel who package samples or who drive transport vehicles should be trained in the proper procedures for safety and good maintenance of samples. If ICAO regulations must be met, staff must have specific training in packaging of dangerous goods. When transporting locally, whether by ambulance, or by clinic or laboratory staff, it is important to maintain sample integrity. Ensure that temperatures are controlled, using ice boxes or air-conditioning, set an acceptable transport time and monitor compliance. Laboratory Quality Management System 69  5-7: Summary Summary A laboratory handbook describing sample collection and providing testing information must be available to everyone who needs this information. It is important to have a system for tracking samples as they move through the laboratory. Establish and implement a policy for sample storage and sample disposal. Maintain sample integrity and assure that all regulations and requirements are met. It may be useful to appoint someone with oversight responsibilities for sample management. Key messages  The laboratory must have good samples in order to ensure accuracy and reliability of testing and confidence in results.  Sample management directly affects patient care and outcome. 70 Laboratory Quality Management System 6. Process control— introduction to quality control  6-1: Introduction Role in quality Process control is an essential element management of the quality management system, Organization Personnel Equipment system and refers to control of the activities employed in the handling of samples and examination processes in order to ensure accurate and reliable testing. Purchasing Process Information and Sample management, discussed in inventory control management Chapter 5, and all quality control (QC) processes are a part of process control. Documents Occurrence and Assessment management records QC monitors activities related to the examination (analytic) phase of testing. The goal of QC is to detect, evaluate, Process Customer Facilities nd correct errors due to test system improvement service and safety failure, environmental conditions or operator performance, before patient results are reported. What is QC? QC is the part of quality management focused on fulfilling quality requirements (ISO 9000:2000 [3.2.10]). Simply put, it is examining “control” materials of known substances along with patient samples to monitor the accuracy and precision of the complete analytic process. QC is required for accreditation purposes. In 1981, the World Health Organization (WHO) used the term "internal quality control" (IQC), which it defined as “a set of procedures for continuously assessing laboratory work and the emergent results”. The terms QC and IQC are sometimes used interchangeably; cultural setting and country may influence preferences for these terms. In the past few years, "internal quality control' has become confusing in some settings because of the different meanings that have been associated with the term. Some manufacturers of test kits for qualitative tests have integrated "built-in" controls in the design of their kits, which they sometimes refer to as internal controls. Other manufacturers include their own control materials with the kits they sell and they refer to these as "internal controls", meaning that the materials are meant specifically for that manufacturer’s kit. Finally, some people refer to any quality control materials that are used in conjunction with test runs as IQC, as in the 1981 WHO definition. 72 Laboratory Quality Management System  6-1: Introduction To avoid confusion, the term "quality control" will be used here to mean use of control materials to monitor the accuracy and precision of all the processes associated with the examination (analytic) phase of testing. QC for varying Quality control processes vary, depending on whether the laboratory examinations methods use methods that produce quantitative, qualitative or semiquantitative results. These examinations differ in the following ways. Quantitative examinations measure the quantity of an analyte present in the sample, and measurements need to be accurate and precise. The measurement produces a numeric value as an end-point, expressed in a particular unit of measurement. For example, the result of a blood glucose test might be reported as 5 mg/dL. Qualitative examinations are those that measure the presence or absence of a substance, or evaluate cellular characteristics such as morphology. The results are not expressed in numerical terms, but in qualitative terms such as “positive” or “negative”; “reactive” or “nonreactive”; “normal” or “abnormal”; and “growth” or “no growth”. Examples of qualitative examinations include microscopic examinations, serologic procedures for presence or absence of antigens and antibodies, and many microbiological procedures. Semiquantitative examinations are similar to qualitative examinations, in that the results are not expressed in quantitative terms. The difference is that results of these tests are expressed as an estimate of how much of the measured substance is present. Results might be expressed in terms such as “trace amount”, “moderate amount”, or “1+, 2+, or 3+”. Examples are urine dipsticks, tablet tests for ketones and some serologic agglutination procedures. In the case of other serologic testing, the result is often expressed as a titre—again involving a number but providing an estimate, rather than an exact amount of the quantity present. Some microscopic examinations are considered semiquantitative because results are reported as estimates of the number of cells seen per low-power field or high-power field. For example, a urine microscopic examination might report 0–5 red blood cells seen per high-power field. Because QC processes differ for these various types of examinations, the presentations for QC will be divided into two chapters. Chapter 7 will address QC for quantitative examinations, and Chapter 8 will address QC for qualitative and semiquantitative examinations. Laboratory Quality Management System 73  6-1: Introduction Elements of a Regardless of the type of examination that is performed, steps for implementing QC programme and maintaining a QC programme include:  establishing written policies and procedures, including corrective actions  training all laboratory staff  ensuring complete documentation  reviewing quality control data. These responsibilities will be described in more detail in Chapters 7 and 8. Summary  QC is part of the quality management system and is used to monitor the examination (analytic) phase of testing.  The goal of QC is to detect, evaluate and correct errors due to test system failure, environmental conditions, or operator performance, before patient results are reported.  Different QC processes are applied to monitor quantitative, qualitative and semiquantitative tests. 74 Laboratory Quality Management System 7. Process control— quality control for quantitative tests  7-1: Overview Role in quality Quality control (QC) is a component management of process control, and is an essential Organization Personnel Equipment system element of the quality management system. It monitors the processes related to the examination phase of testing and allows for detecting errors in the testing Purchasing and Process Information system. These errors may be due to test inventory control management system failure, adverse environmental conditions or operator performance. QC gives the laboratory confidence that test Documents Occurrence and Assessment results are accurate and reliable before records management patient results are reported. This chapter explains how quality control Process Customer Facilities and methods are applied to quantitative improvement service safety laboratory examinations. Overview of Quantitative tests measure the quantity of a substance in a sample, yielding a the process numeric result. For example, the quantitative test for blood glucose can give a result of 5 mg/dL. Since quantitative tests have numeric values, statistical tests can be applied to the results of QC material to differentiate between test runs that are “in control” and “out of control”. This is done by calculating acceptable limits for control material, then testing the control with the patient’s samples to see if it falls within established limits. As a part of the quality management system, the laboratory must establish a QC programme for all quantitative tests. Evaluating each test run in this way allows the laboratory to determine if patient results are accurate and reliable. Implementation The steps for implementing a QC programme are: process  establish policies and procedures  assign responsibility for monitoring and reviewing  train all staff in how to properly follow policies and procedures  select good QC material  establish control ranges for the selected material  develop graphs to plot control values—these are called Levey–Jennings charts  establish a system for monitoring control values  take immediate corrective action if needed  maintain records of QC results and any corrective actions taken. 76 Laboratory Quality Management System  7-2: Control materials Defining control Controls are substances that contain an established amount of the substance materials being tested—the analyte. Controls are tested at the same time and in the same way as patient samples. The purpose of the control is to validate the reliability of the test system and evaluate the operator’s performance and environmental conditions that might impact results. Differentiating It is important not to confuse calibrators and control materials. Calibrators controls and are solutions with a specified defined concentration that are used to set or calibrators calibrate an instrument, kit, or system before testing is begun. Calibrators are often provided by the manufacturer of an instrument. They should not be used as controls since they are used to set the instrument. Calibrators are sometimes called standards, but the term calibrator is preferred.They usually do not have the same consistency as patients’ samples. Characteristics of It is critical to select the appropriate control materials. Some important control materials characteristics to consider when making the selection are:  Controls must be appropriate for the targeted diagnostic test—the substance being measured in the test must be present in the control in a measurable form.  The amount of the analyte present in the controls should be close to the medical decision points of the test; this means that controls should check both low values and high values.  Controls should have the same matrix as patient samples; this usually means that the controls are serum based, but they may also be based on plasma, urine or other materials. Because it is more efficient to have controls that last for some months, it is best to obtain control materials in large quantities. Types and Control materials are available in a variety of forms. They may be frozen, freeze- sources of dried or chemically preserved. The freeze-dried or lyophilized materials must be control material reconstituted, requiring great care in pipetting in order to ensure the correct concentration of the analyte. Control materials may be purchased, obtained from a central or reference laboratory, or made in-house by pooling sera from different patients. Purchased controls may be either assayed or unassayed. Assayed controls have a predetermined target value, established by the manufacturer. When using assayed controls, the laboratory must verify the value using its own methods. Assayed controls are more expensive to purchase than unassayed controls. When using either unassayed or “in-house” controls, the laboratory must establish the target value of the analyte. Laboratory Quality Management System 77  7-2: Control materials The use of in-house controls requires resources to perform validation and testing steps. An advantage is that the laboratory can produce very large volumes with exact specifications. Remember that QC materials are usually serum based. Universal precautions should be used when handling. Choosing When choosing controls for a particular method, select values that cover medical controls decision points, such as one with a normal value, and one that is either high or low, but in the medically significant range. Controls are usually available in "high", "normal" and "low" ranges. Shown in the graphic are normal, abnormal high and low, and critical high and low ranges. For some assays, it may be important to include controls with values near the low end of detection. PATIENT CONTROLS Critical ? Abnormal C O N TRO L Critical high and low range Normal range Normal C O N TRO L Abnormal high Abnormal and low ranges C O N TRO L Critical Preparing and When preparing and storing QC materials, it is important to carefully adhere to storing control the manufacturer’s instructions for reconstituting and storage. If in-house control material material is used, freeze aliquots and place in the freezer so that a small amount can be thawed and used daily. Do not thaw and refreeze control material. Monitor and maintain freezer temperatures to avoid degradation of the analyte in any frozen control material. Use a pipette to deliver the exact amount of required diluent to lyophilized controls that must be reconstituted. 78 Laboratory Quality Management System  7-3: Establishing the value range for the control material Assaying control Once the appropriate control materials are purchased or prepared, the next step over time is to determine the range of acceptable values for the control material. This will be used to let the laboratory know if the test run is “in control” or if the control values are not reading properly—“out of control”. This is done by assaying the control material repeatedly over time. At least 20 data points must be collected over a 20–30-day period. When collecting this data, be sure to include any procedural variation that occurs in the daily runs; for example, if different testing personnel normally do the analysis, all of them should collect part of the data. Once the data is collected, the laboratory will need to calculate the mean and standard deviation of the results. A characteristic of repeated measurements is that there is a degree of variation. Variation may be due to operator technique, environmental conditions or the performance characteristics of an instrument. Some variation is normal, even when all of the factors listed above are controlled. The standard deviation gives a measure of the variation.This process is illustrated below. Obtain control material Run each control 20 times over 30 days 3 SD 2 SD 1 SD Calculate mean and Mean + 1, 2, 3 standard deviations 1 SD 2 SD 3 SD One of the goals of a QC programme is to differentiate between normal variation and errors. A few theoretical concepts are important because they are used to Characteristics establish the normal variability of the test system. QC materials are of repeated run to quantify the variability and establish a normal range, and to measures decrease the risk of error. The variability of repeated measurements will be distributed around a central point or location. This characteristic of repeated measurements is known as central tendency. Laboratory Quality Management System 79  7-3: Establishing the value range for the control material The three measures of central tendency are:  Mode—the number that occurs most frequently.  Median—the central point of the values when they are arranged in numerical sequence.  Mean—the arithmetic average of results.The mean is the most commonly used measure of central tendency used in laboratory QC. Statistical Statistical notations are symbols used in mathematical formulas to calculate notations statistical measures. For this chapter, the symbols that are important to know are:  the sum of  number of data points (results or observations) X1 individual result X1 – Xn data point 1–n where n is the last result X the symbol for the mean  the square root of the data. Mean The formula for the mean is: X1 + X2 + X 3... Xn X= N As an example of how to calculate a mean, consider enzyme-linked immunosorbent assay (ELISA) testing. The method is to gather data as ratios, add the values and divide by the number of measurements. Before calculating The purpose of obtaining 20 data points by running the QC sample is to quantify QC ranges normal variation and establish ranges for QC samples. Use the results of these measurements to establish QC ranges for testing. If one or two data points appear to be too high or low for the set of data, they should not be included when calculating QC ranges. They are called “outliers”.  If there are more than 2 outliers in the 20 data points, there is a problem with the data and it should not be used.  Identify and resolve the problem and repeat the data collection. Normal If many measurements are taken, and the results are plotted on a graph, the values distribution form a bell-shaped curve as the results vary around the mean. This is called a normal distribution (also termed Gaussian distribution). 80 Laboratory Quality Management System  7-3: Establishing the value range for the control material The distribution can be seen if data points are plotted on the x-axis and the frequency with which they occur on the y-axis. The normal curve shown (right) is really a theoretical curve obtained when a large Frequency number of measurements are plotted. It is assumed that the types of measurements used for quantitative QC are normally distributed based on this theory. Accuracy and If a measurement is repeated many times, mean precision the result is a mean that is very close to the true mean. Accuracy is the closeness of a measurement to its true value. Precision is the amount of variation in the measurements.  The less variation a set of measurements has, the more precise it is.  In more precise measurements, the width of the curve is smaller because the measurements are all closer to the mean. Bias is the difference between the expectation of a test result and an accepted reference method. The reliability of a method is judged in terms of accuracy and precision. A simple way to portray precision and accuracy is to think of a target with a Target illustration bull’s eye. The bull’s eye represents the accepted reference value which is the true, unbiased value. If a set of data is clustered around the bull’s eye, it is accurate. The closer together the hits are, the more precise they Accurate and Precise but Imprecise precise biased are. If most of the hits are in the the bull’s eye, as in the figure on the left, they are both precise and accurate. The values in the middle figure are precise but not Accurate = precise but not biased accurate because they are clustered together but not at the bull’s eye.The figure on the right shows a set of hits that are imprecise. Measurements can be precise but not accurate if the values are close together but do not hit the bull’s eye.These values are said to be biased.The middle figure demonstrates a set of precise but biased measurements. Laboratory Quality Management System 81  7-3: Establishing the value range for the control material The purpose of quality control is to monitor the accuracy and precision of laboratory assays before releasing patient results. Measures of The methods used in clinical laboratories may show different variations about the variability mean; hence, some are more precise than others. To determine the acceptable variation, the laboratory must compute the standard deviation (SD) of the 20 control values.This is important because a characteristic of the normal distribution is that, when measurements are normally distributed:  68.3% of the values will fall within –1 SD and +1 SD of the mean  95.5% fall within –2 SD and +2 SD  99.7% fall between –3 SD and +3 SD of the mean. Knowing this is true for all normally shaped distributions allows the laboratory to establish ranges for QC material. Once the mean and SD are computed for a set of measurements, a QC material that is examined along with patients' samples should fall within these ranges. SD is a measurement of variation in a set of results. It is very useful to the Standard laboratory in analyzing QC results. deviation The formula for calculating standard deviation is: SD = (X1 – X)2 n–1 The number of independent data points (values) in a data set are represented by “n”. Calculating the mean reduces the number of independent data points to n – 1. Dividing by n –1 reduces bias. The values of the mean, as well as the values of + 1, 2 and 3 SDs are needed to Calculating develop the chart used to plot the daily control values. acceptable limits for  To calculate 2 SDs, multiply the SD by 2 then add and subtract each result from the control the mean.  To calculate 3 SDs, multiply the SD by 3, then add and subtract each result from the mean. For any given data point, 68.3% of values will fall between + 1 SD, 95.5% between 82 Laboratory Quality Management System  7-3: Establishing the value range for the control material + 2 SD and 99.7% between + 3 SD of the mean. When only one control is used, we consider an examination run to be “in control” if a value is within 2 SD of the mean. The coefficient of variation (CV) is the SD expressed as a percentage of the mean. Coefficient of variation CV (%) = SD x 100 Mean The CV is used to monitor precision. When a laboratory changes from one method of analysis to another, the CV is one of the elements that can be used to compare the precision of the methods. Ideally, the value of the CV should be less than 5%. Laboratory Quality Management System 83  7-4: Graphically representing control ranges Using graphs Once the appropriate range of control values has been established, the laboratory for analysis and will find it very useful to represent the range graphically for the purpose of daily monitoring monitoring. The common method for this graphing is the use of Levey–Jennings charts. Developing In order to develop Levey–Jennings charts for daily use in the laboratory, the data for Levey– first step is the calculation of the mean and SD of a set of 20 control values as Jennings charts explained in 7-3. Levey–Jennings A Levey–Jennings chart can then be drawn, showing the mean value as well as chart + 1, 2, and 3 SD. The mean is shown by drawing a line horizontally in the middle of the graph and the SD are marked off at appropriate intervals and lines drawn horizontally on the graph, as shown below. Draw lines for mean and SD (calculated from 20 controls) Chart name: Lot number: 196.5 +3 SD 194.5 +2 SD 192.5 +1 SD 190.5 MEAN 188.5 –1 SD 186.5 –2 SD 184.5 –3 SD Days This Levey–Jennings chart was developed using 20 repeated measurements of the control value. In order to use the Levey–Jennings chart to record and monitor daily control values, label the x-axis with days, runs,or other intervals used to run QC. Label the chart with the name of the test and the lot number of the control being used. 84 Laboratory Quality Management System  7-5: Interpreting quality control data Plotting control A QC sample tested along with patient’s samples can now be used to determine if values daily runs are “in control”. A control sample must be run with each set of patient samples. Run the control and plot it on the Levey–Jennings chart. If the value is within +2 SD, the run can be accepted as “in-control”. Draw lines for mean and SD (calculated from 20 controls) Chart name: Lot number: 196.5 +3 SD 194.5 +2 SD 192.5 +1 SD 190.5 MEAN 188.5 –1 SD 186.5 –2 SD 184.5 –3 SD Days The values on the chart are those run on days 1, 2 and 3 after the chart was made. In this case, the second value is “out of control” because it falls outside of 2 SD. When using only one QC sample, if the value is outside 2 SD, that run is considered “out of control” and the run must be rejected. Number of If it is possible to use only one control, choose one with a value that lies within controls used the normal range of the analyte being tested. When evaluating results, accept all runs where the control lies within +2 SD. Using this system, the correct value will be rejected 4.5% of the time. In order to improve efficiency and accuracy, a system using two or three controls for each run can be employed. Then another set of rules can be used to avoid rejecting runs that may be acceptable. These rules were applied to laboratory QC by a clinical chemist named James Westgard. This Westgard multirule system requires running two controls of different target values for each set of examinations, developing a Levey–Jennings chart for each, and applying the rules. The use of three controls with each run gives even higher assurance of accuracy of the test run. When using three controls, choose a low, a normal and a high range value. There are also Westgard rules for a system with three controls. Laboratory Quality Management System 85  7-5: Interpreting quality control data Detecting Errors that occur in the testing process may be either random or systematic. error With random error, there will be a variation in QC results that show no pattern. This type of error generally does not reflect a failure in some part of the testing system, and is therefore not like to reccur. Random error is only a cause for rejection of the test run if it exceeds +2 SD. Systematic error is not acceptable, as it indicates some failure in the system that can and should be corrected. Examples of evidence of systematic error include:  shift—when the control is on the same side of the mean for five consecutive runs;  trend—when the control is moving in one direction, and appears to be heading toward an out-of-control value. Even when a control value falls within 2 SD, it can be a cause for concern. Levey– Jennings charts can help distinguish between normal variation and systematic error. Shifts and Shifts in the mean occur when an abrupt change is followed by six or more trends consecutive QC results that fall on one side of the mean, but typically within 95% range as if clustered around a new mean. On the sixth occasion this is called a shift and results are rejected. Trends occur when values gradually, but continually, move in one direction over six or more analytical runs. Trends may display values across the mean, or they may occur only on one side of the mean. On the sixth occasion, this is determined to be a trend and results are rejected. The source of the problem must be investigated and corrected before patients’ samples are reported. Measurement As variation occurs in measurements, uncertainty exists as to the true value. uncertainty Uncertainty represents a range of values in which the true value is reasonably expected to lie. In most situations, measurement uncertainty is estimated at “95% coverage”. For most instances, a range of +2 SD is accepted as measurement uncertainty that is explained by random variation. But the degree of variation also depends on the method used. Methods that are more precise have less uncertainty because the amount of variation included in the 95% limits is smaller. Laboratories should strive to use methods that have a high degree of precision, and always follow standard operating procedures. 86 Laboratory Quality Management System  7-6: Using quality control information When QC is out When the QC sample that is used in a test run is out of the acceptable range, of range the run is considered to be “out of control”.When this happens, there are several steps that the laboratory must follow.  The testing process should be stopped and the technologist must immediately try to identify and correct problems.  Once possible sources of error have been identified and corrections have been made, the control material should be rechecked. If they read correctly, then patient samples, along with another QC specimen, should be repeated. Do not simply repeat the testing without looking for sources of error and taking corrective action.  Patient results must not be reported until the problem is resolved and the controls indicate proper performance. Problem When attempting to solve QC problems, it is useful to have established policies solving and procedures for remedial action. Often, manufacturers of either equipment or reagents will provide guidelines that can be helpful. Use any troubleshooting guides that are available. Possible problems to consider include:  degradation of reagents or kits  control material degradation  operator error  failure to follow manufacturer’s instructions  an outdated procedure manual  equipment failure  calibration error. Laboratory Quality Management System 87  7-7: Summary Summary A QC programme for quantitative tests is essential to ensuring accuracy and reliability of laboratory testing. The laboratory must establish a QC programme that monitors all quantitative tests. The programme will have written policies and procedures that are followed by all laboratory staff. The overall responsibility of managing the QC programme is usually assigned to the quality manager, who monitors and reviews all QC data on a regular basis.The recording of the QC data must be complete and easy to access. For quantitative testing, statistical analysis can be used for the monitoring process, and the use of Levey–Jennings charts provides a very useful visual tool for this monitoring. When controls are out of range, corrective action and troubleshooting must be undertaken; the problem must be fixed before reporting patient results. Therefore, good protocols for troubleshooting and corrective action are an important part of the QC process. Key messages  A QC programme allows the laboratory to differentiate between normal variation and error.  The QC programme monitors the accuracy and precision of laboratory assays.  The results of patient testing should never be released if the QC results for the test run do not meet the laboratory target values. 88 Laboratory Quality Management System 8. Process control— quality control for qualitative and semiquantitative procedures  8-1: Overview Quality control (QC) is a component Role in quality of process control, which is a Organization Personnel Equipment management major element of the quality system management system. It monitors the processes related to the examination phase of testing and allows for detecting Purchasing Process Information errors in the testing system. These and inventory control management errors may be due to test system failure, adverse environmental conditions or operator performance. QC gives the Documents Occurrence laboratory confidence that test results and management Assessment records are accurate and reliable before patient results are reported. Facilities Process Customer This chapter explains how QC improvement service and safety methods are applied to qualitative and semiquantitative laboratory examinations. Qualitative and Qualitative examinations are those semiquantitative that measure the presence or absence examinations of a substance, or evaluate cellular characteristics such as morphology. The results are not expressed in numerical terms, but in descriptive or qualitative terms such as “positive”, “negative”, “reactive”, “nonreactive”, “normal” or “abnormal”. Examples of qualitative examinations include microscopic examinations for cell morphology or presence of parasitic organisms, serologic procedures for presence or absence of antigens and antibodies, some microbiological procedures and some molecular techniques. Semiquantitative examinations are similar to qualitative examinations; testing does not measure the precise 90 Laboratory Quality Management System  8-1: Overview quantity of a substance. The difference is that results of these tests are expressed as an estimate of how much of a measured substance is present. This estimate is sometimes reported as a number. Therefore, test results for semiquantitative tests may be shown as “trace amount”, “1+, 2+ or 3+”, or positive at 1:160 (titre or dilution). Examples of semiquantitative examinations are urine dipsticks, tablet tests for ketones and serological agglutination procedures. Some microscopic examinations are considered semiquantitative because results are reported as estimates of the number of cells seen per low-power field or high- power field. For example, a urine microscopic examination might report 0–5 red blood cells seen per high-power field. Important As with quantitative procedures, it is important to verify that results of qualitative concepts and semiquantitative examinations are correct prior to reporting them to the requesting health care provider. Conducting QC for many of these tests is not as easily accomplished as with quantitative tests. Therefore, it becomes essential that other processes within the quality system are carefully conducted, in addition to traditional QC methods. Following are some important overarching concepts for quality that apply to qualitative and semiquantitative tests.  Sample management is important in all laboratory testing. Examinations that are dependent on a viable organism in the sample may need closer monitoring and better communication with nonlaboratory staff (see Chapter 5).  Dedicated, professional staff who understand the principles of QC are key to quality.  Incubators, refrigerators, microscopes, autoclaves and other equipment must be maintained and monitored carefully (see Chapter 3).  Positive and negative controls must be used to monitor the effectiveness of test procedures that use special stains or reagents and tests with end-points such as agglutination, colour change or other non-numeric results.  Reagents should be stored according to the manufacturer’s instructions, labelled with the date they are opened and put into use, and discarded at the expiration date (see Chapter 4).  Keeping records of all QC processes and corrective actions is necessary for continual improvement of the laboratory quality system (see Chapter 16).  When problems occur, investigate, correct, and repeat patient testing (see Chapter 14). If QC results are not what are expected, do not report patient results. Laboratory Quality Management System 91  8-2: Quality control materials Qualitative and semiquantitative examinations include tests that utilize a variety of Control control materials.These controls may be built-in (on-board or procedural) controls, types traditional controls that mimic patient samples, or stock cultures for use with microbiological examinations. Built-in controls are those that are integrated into the Built-in design of a test system such as a test kit device.Usually,the controls device is marked with designated areas where coloured lines, bars or dots should appear to indicate success or failure of positive and negative controls, and these controls are performed automatically with each test.The manufacturer’s product instructions may also refer to these as procedural controls, on-board controls or internal controls. Most built-in controls monitor only a portion of the examination phase, and they vary from one test to another as to what is being monitored. For example, built-in controls for some kits may indicate that all the reagents impregnated into the device are active and working properly, whereas built-in controls for other kits may only indicate that a sample was added and solutions flowed through the device correctly. It is important to carefully read the instructions provided by the manufacturer to understand what the built-in controls monitor, and to determine whether additional controls may be needed. Examples of test kits with built-in controls are rapid tests that detect the presence of antigens or antibodies, such as those for infectious disease (human immunodeficiency virus [HIV], influenza, lyme disease, streptococcal infection, infectious mononucleosis), drugs of abuse, pregnancy or faecal occult blood. Even though these built-in controls give some degree of confidence, they do not monitor for all conditions that could affect test results. It is advisable to periodically test traditional control materials that mimic patient samples, for added confidence in the accuracy and reliability of test results. In some settings, these built-in controls are referred to as internal controls. Traditional control materials are made to mimic patient samples and they are tested Traditional with the patient samples to evaluate the examination component. Positive controls controls have known reactivity and negative controls are nonreactive for the analyte being tested. The controls should have the same composition, or matrix, as patient samples, including viscosity, turbidity and colour, in order to properly evaluate the test performance. Control materials are often lyophilized when received, and need to be carefully reconstituted before use. Some manufacturers may provide 92 Laboratory Quality Management System  8-2: Quality control materials these controls with their test kits but, more frequently, they need to be purchased separately. Traditional controls evaluate the testing process more broadly than built-in controls. They assess the integrity of the entire test system, the suitability of the physical testing environment (temperature, humidity, level workspace), and whether the person conducting the test performs it correctly. Positive and negative controls are recommended for many qualitative and semiquantitative tests, including some procedures that use special stains or reagents, and tests with end-points such as agglutination or colour change. These controls should generally be used with each test run. Use of controls will also help to validate a new lot number of test kits or reagents, to check on temperatures of storage and testing areas, and to evaluate the process when new testing personnel are carrying out the testing. Things to keep in mind when using traditional controls for qualitative or semiquantitative tests are:  test control materials in the same manner as testing patient samples;  use a positive and negative control, preferably once each day of testing, or at least as often as recommended by the manufacturer;  choose positive controls that are close to the cut-off value of the test, to be sure the test can detect weak positive reactions;  for agglutination procedures, include a weak positive control as well as a negative control and a stronger positive control;  for tests with an extraction phase, such as some rapid group A Streptococcus tests, choose controls that are capable of detecting errors in the extraction process. Stock QC in microbiology requires use of live control organisms with predictable cultures reactions to verify that stains, reagents and media are working correctly. They must be kept on hand and carefully maintained in the form of stock and working cultures. For each reaction, organisms with both positive and negative results should be tested. The following organizations offer reference strains, which are available from local distributors:  American Type Culture Collection (ATCC)  National Type Culture Collection (NTCC, United Kingdom)  Pasteur Institute Collection (CIP, France). Purchased reference strains are usually lyophilized and kept in the refrigerator. Once they are reconstituted, plated and checked for purity, they can be used to make working cultures for quality control. Some laboratories may choose to use isolates from their own laboratories for QC. If so, they should be monitored closely to verify that reactions tested are sustained over time. Laboratory Quality Management System 93  8-3: Quality control of stains Procedures In performing many qualitative and semiquantitative procedures, stains are needed using stains for evaluating microscopic morphology of cells, parasites or microbes, or to determine their presence or absence. Stains are used for microscopic procedures that provide information for either preliminary or definitive diagnosis. These are frequent in haematology, urinalysis, cytology, histology, microbiology, parasitology and other laboratory areas. In microbiology, permanent stains such as acridine orange, trichrome and iron- haematoxylin for faecal parasites, and Giemsa stain for malaria, are frequently used. Gram stains are used for identification of bacteria and yeast from colonies and samples. Acid-fast stains are particularly important for preliminary diagnosis, since growth of mycobacteria takes several weeks. In many sites, Mycobacterium tuberculosis (TB) cultures are not available and acid-fast smears will provide the final diagnosis for patients. For wet mounts, iodine solutions are used to detect cysts and eggs in faecal samples, and potassium hydroxide preparations are used to detect fungal elements. Examination of blood smears requires a stain that allows for clear visualization of red blood cells, white blood cells, platelets and inclusions within cells. Differentiation of cells in blood most frequently employs a Wright stain, and some haematology procedures use special stains to help differentiate infection from leukaemia. Cytology and histology tests require a wide variety of stains that provide valuable information for diagnosis. Many other stains are available to laboratory staff for special uses. The common elements for QC are the same: the stains should be prepared and stored properly, and checked to be sure they perform as expected. Remember that many of the microscopic examinations that rely on stains are critical in diagnosis of many diseases. Stain Some stains can be purchased commercially, but others must be prepared by management the laboratory, following an established procedure. Once stains are made, their bottles should be labelled with the following information:  name of the stain  concentration  date prepared  date placed in service  expiration date/shelf life  preparer’s initials. 94 Laboratory Quality Management System  8-3: Quality control of stains It may be useful to keep a logbook for recording information on each stain in use, including the lot number and date received. The expiration date must be noted on the label. Some stains deteriorate and lose their ability to produce the correct reactions. Stains should be stored at the correct temperature at all times and in an appropriate staining bottle. Some stains must be protected from light. In some cases, working solutions can be made from stock solutions. If so, storage of working solutions should be carefully monitored. Quality Because of their importance, stains should be checked each day of use with control positive and negative QC materials, to make sure their reagents are active and they provide the intended results. In most cases, positive and negative controls should be stained with each batch of patients’ slides. All QC results must be recorded each time they are run. Stains should also be examined to look for precipitation or crystal formation, and to check for bacterial contamination. Careful maintenance and care of the stock and working solutions of stains is an essential component in a system to provide good quality in microscopic examinations. Be aware that many stains are toxic, therefore, take appropriate safety precautions when working with them. Laboratory Quality Management System 95  8-4: Quality control of microbiological media QC is essential The quality of media used in the microbiology laboratory is crucial to achieving for media optimal and reliable results. Some media are essential to isolation of microbes, so it is imperative that they function as expected. QC procedures provide the confidence that media has not been contaminated prior to use, and that it supports the growth of the organism with which it was inoculated. Verifying The performance characteristics of all media used in the laboratory must be performance verified by the appropriate QC methods. For media that is prepared in-house, this evaluation must be conducted for each batch prepared; for all commercially prepared media, the performance verification will be performed for each new lot number. In all cases, in-house and purchased media should be carefully checked for:  sterility—incubate overnight before use  appearance—check for turbidity, dryness, evenness of layer, abnormal colour  pH  ability to support growth—using stock organisms  ability to yield the appropriate biochemical results—using stock organisms. The laboratory must maintain sufficient stock organisms to check all its media Use of control and test systems. Some examples of important stock organisms, and the media organisms for checked, include: verification  Escherichia coli (ATCC 25922): MacConkey or eosin methylene blue (EMB), some antimicrobial susceptibility testing;  Staphylococcus aureus (ATCC 25923): blood agar, mannitol salt and some antimicrobial susceptibility tests;  Neisseria gonorrhoeae (ATCC 49226): chocolate agar and Thayer–Martin agar. 96 Laboratory Quality Management System  8-4: Quality control of microbiological media For selective media, inoculate a control organism that should be inhibited as well as one that should grow. Discard any batch of media that does not work as expected. For differential media, inoculate the media with control organisms that should demonstrate the required reactions. For example, inoculate both lactose- fermenting and non-lactose-fermenting organisms onto EMB or MacConkey agar to verify that the colonies exhibit correct visual appearance. Note: sheep and horse blood are preferred in preparing media for routine cultures. Blood agar made from human blood should not be used as it will not demonstrate the correct haemolysis pattern for identification of certain organisms, and it may contain inhibitory substances. In addition, human blood can be biohazardous. In-house media It is important to keep careful records for media that is prepared in the laboratory. preparation A logbook should be maintained that records: records  date and preparer's name  name of the medium, the lot number and manufacturer  number of prepared plates, tubes, bottles or flasks  assigned lot and batch numbers  color, consistency and appearance  number of plates used for QC  sterility test results at 24 and 48 hours  growth test(s)  pH. Laboratory Quality Management System 97  8-5: Summary Examinations Qualitative and semiquantitative examinations are those that give non-numerical with non- results. Qualitative examinations measure the presence or absence of a substance, numerical results or evaluate cellular characteristics such as morphology. Semiquantitative examinations provide an estimate of how much of the measured substance is present. Qualitative and semiquantitative testing must be monitored by QC processes. These processes should use controls that mimic patient samples as much as possible. Quality controls that check kits, reagents, stains and microbiological media and ensure that they work as expected must be used whenever they are available. The laboratory must establish a QC programme for all of its qualitative and semiquantitative tests. In establishing this programme, set policies, train staff and assign responsibilities, and ensure that all resources needed are available. Make sure that recording of all QC data is complete, and that appropriate review of the information is carried out by the quality manager and the laboratory director. Key messages  All staff must follow the QC practices and procedures.  Always record QC results and any corrective actions that are taken.  If QC results are not acceptable, do not report patient results. 98 Laboratory Quality Management System 9. Assessment—audits  9-1: Overview Organization Personnel Equipment Role in quality Assessment is an important element of management the 12 quality system essentials. It is the system means for determining the effectiveness Purchasing and Process Information of a laboratory’s quality management inventory control management system through internal and external audits, and evaluation of performance in an external quality assessment (EQA) Documents Occurrence and Assessment programme. This chapter is focused on records management descriptions of internal and external audits; EQA will be described in Chapter 10. Process Customer Facilities and improvement service safety What is An assessment can be defined as the systematic examination of some part assessment? (or sometimes all) of the quality management system to demonstrate to all concerned that the laboratory is meeting regulatory, accreditation and customer requirements. Central-level laboratories are generally familiar with assessment processes, as most will have had some kind of assessment by an external group. However, intermediate or peripheral-level laboratories may not be assessed very often in resource-limited countries. Accepted standards, whether international, national, local, or standards from accrediting organizations, form the basis for laboratory assessment. In that respect, assessment is interrelated with norms and accreditation (Chapter 11). In an assessment, someone is asking the following questions:  What procedures and processes are being followed in the laboratory; what is being done?  Do the current procedures and processes comply with written policies and procedures? And in fact, are there written policies and procedures?  Do written policies and procedures comply with standards, regulations, and requirements? Why perform an Assessments are performed in a variety of ways and under a number of different assessment? circumstances.The International Organization for Standardization (ISO) standards are very specific about assessment requirements, and the term “audit” is used instead of “assessment”. The terms may be considered interchangeable, and local usage will determine the actual terminology required.The ISO definition for audit is a “systematic, independent and documented process for obtaining evidence and evaluating it objectively to determine the extent to which required criteria are fulfilled.” 100 Laboratory Quality Management System  9-1: Overview An assessment, or audit, allows the laboratory to understand how well it is performing when compared to a benchmark or standard. Any gaps or nonconformities in performance can show if the policies and procedures that the laboratory has set require revision or are not being followed. A laboratory needs this information about its performance for:  planning and implementing the quality system  monitoring effectiveness of the quality system  correcting any deficiencies that are identified  working toward continuous improvement. External and Assessments conducted by groups or agencies from outside the laboratories internal audits are called external audits. They can include assessments for the purpose of accreditation, certification or licensure. Another type of assessment that laboratories can utilize is the internal audit, where staff working in one area of the laboratory conduct assessments on another area of the same laboratory. This provides information quickly and easily on how the laboratory is performing and whether it is in compliance with policy requirements. Test The patient selection Sample collection Pr e e xa mi na t i o n ph ase Sample transport Laboratory analysis Examination phase t io n p a s e h Report i na creation am Report transport ex st Po ti on R e s ult int e r p r e t a Laboratory path Audits should include the evaluation of steps in the whole laboratory path of of workflow workflow.They should be able to detect problems throughout the entire process. Laboratory Quality Management System 101  9-1: Overview Auditing The value of a well-designed audit is that it will reveal weaknesses in the pre- examination, examination and post-examination phases. During audits, information is gathered about:  processes and operating procedures  staff competence and training  equipment  environment  handling of samples  quality control and verification of results  recording and reporting practices. The findings are compared with the laboratory’s internal policies and to a standard or external benchmark.Any breakdown in the system or departure from procedures will be identified. 102 Laboratory Quality Management System  9-2: External audit External Assessments conducted by groups or agencies from outside the laboratory are audits called external audits. Some examples of external auditors are described below.  Health authorities may assess laboratories to evaluate the quality of performance, or compliance with licensing requirements and national regulations. They may also assess as part of a capacity strengthening plan of action, or for public health programme needs.  Accreditation bodies are organizations that provide accreditation or certification. When a laboratory seeks accreditation, an initial audit will be required to evaluate compliance with standards. In order to maintain accredited status, the accreditation bodies will require periodic audits (see Chapter 11).  An audit may be requested by major public health programmes, or by agencies that provide funding for programmes. These groups want to ensure that quality standards are being met and that quality practices are in place. International programmes such as the World Health Organization (WHO) Polio Initiative regularly assess disease-specific laboratories according to their own standards with their own checklists; for example, WHO polio laboratory accreditation standard and WHO measles accreditation standard. Standards In conducting external audits, the assessors will verify that laboratory policies, processes and procedures are documented and comply with designated standards. Different standards can be used for the assessment processes, ranging from international standards to a locally developed checklist. Laboratory management must demonstrate to the assessment team that all requirements as laid down in the standard are being followed. Preparation When a laboratory undergoes an external audit, the laboratory needs to be fully prepared so that the assessment experience is as easy as possible for both the assessors and the laboratory staff, and so the assessment yields the maximum amount of information. To be ready for the external audit, it is necessary to:  plan thoroughly and carefully;  organize everything ahead of time, including documents and records, to save valuable time during the audit;  make all staff aware of the audit, and arrange schedules so that all staff needed for the audit will be available. On occasion, some external audits might occur without prior notification. In this case, the laboratory would not be able to make special preparation, so the laboratory should always be sure its system is operating properly. Laboratory Quality Management System 103  9-2: External audit Audit report and After the audit, the recommendations of the assessors are often presented as a plan of action verbal summary to the laboratory management and staff, which are then followed by a thorough written report. After the external audit has been completed the laboratory should:  review the recommendations of the assessors;  identify gaps or nonconformities, learning where benchmarks or standards were not fully met;  plan to correct the nonconformities—this will result in a plan for all needed corrective actions to be taken by the laboratory, which should include a timeline, as well as indicate who is responsible for doing the work;  record all results and actions taken so that the laboratory has a permanent record of the event—often a written report is useful for preserving all information. 104 Laboratory Quality Management System  9-3: Internal audit Purpose Most technologists in central-level laboratories are relatively familiar with external audits; however, the idea of conducting internal audits might be new to some people. An internal audit allows the laboratory to look at its own processes. In contrast to external audits, the advantages of internal audits are that laboratories can perform them as frequently as needed, and at very little or no cost. Internal audits should be a part of every laboratory quality system, and are a requirement of ISO standards.1 The audits should be conducted regularly and when problems that need to be studied have been identified. For example, internal audits should be performed after receiving a poor performance on a proficiency testing survey, after an increased number of unexpected abnormal results for a particular test, or after an increase in expected turnaround time. Value of an The internal audit is a valuable tool in a quality management system. An internal internal audit audit can help the laboratory to:  prepare for an external audit;  increase staff awareness of quality system requirements;  identify the gaps or nonconformities that need to be corrected—the opportunities for improvement;  understand where preventive or corrective action is needed;  identify areas where education or training needs to occur;  determine if the laboratory is meeting its own quality standards. Internal audit and ISO standards put much emphasis on internal audits, and for those seeking ISO accreditation under ISO, internal audits are required. ISO requirements state that:  the laboratory must have an audit programme;  the auditors should be independent of the activity;  audits must be documented and reports retained;  results must be reported to management for review;  problems identified in the audits must be promptly addressed and appropriate actions taken. 1 ISO 19011:2002. Guidelines for quality and/or environmental systems auditing. Geneva, International Organization for Standardization, 2002. Laboratory Quality Management System 105  9-4: Internal audit programme Responsibilities The laboratory director is responsible for setting overall policies for the internal audit programme. Responsibilities will include assigning authority for the programme (usually to the quality manager) and supporting the corrective action measures that are indicated. It is essential that the laboratory director be fully informed about the results of all internal audits. The quality manager is responsible for organizing and managing the laboratory internal audit programme. This includes setting a timeframe for the audits, choosing and training the auditors, and coordinating the process. The follow-up activities will also usually be the responsibility of the quality manager, and these include managing all corrective action efforts. The quality manager must be sure that laboratory management and the laboratory staff are fully informed about outcomes of the audit. The commitment of laboratory management and the quality manager will be key to successfully establishing a process for internal audits. Process The quality manager or other designated qualified personnel should organize the internal audit following these steps:  develop a formal plan  prepare a checklist based on selected guidelines or standards  meet with all staff and explain the audit process  select staff to serve as auditors  collect and analyze information  share results with staff  prepare a report  present the report to management  retain the report as a permanent laboratory record. Select areas In order to facilitate the internal audit process, it is useful to keep it simple. Focus for audits on defined areas of the laboratory activities, identified by issues such as customer complaints or quality control problems. Narrowing the audit to the specific corresponding process will save time and energy. Perform short and frequent audits rather than initiating an annual comprehensive and overwhelming effort. Establish a ISO 15189:2007 [4.14.2] states: “The main elements of the quality management schedule system should normally be subject to internal audit once every twelve months”. This requirement does not mean that a complete audit needs to be done annually. Rather, it means that over a period of a year, every part of the laboratory should have at least one inspection. Doing a number of small, bench-specific or section- specific audits is much easier than trying to do them all at the same time. Establish a policy that, at specified intervals, some section of the laboratory or a specific process will have an internal audit. In general, audit regularly and consider three to six-month intervals between audits. If audits reveal specific problems, it may be necessary to include more frequent audits. 106 Laboratory Quality Management System  9-4: Internal audit programme Checklists and When developing checklists for internal audits: forms used  Take into account any established national policies and standards. For example, most countries have standards for human immunodeficiency virus (HIV) and tuberculosis testing; laboratories conducting this testing need to ensure checklists reflect these standards.  Ensure checklists are easy to use and include areas for recording information.  Focus on specific tests or processes; whatever the area of focus, address all areas of the quality system. If auditing enzyme-linked immunosorbent assay (ELISA) tests, consider personnel competency or equipment maintenance, sample handling, and quality control associated with these tests. Forms will be needed for recording corrective actions and for making reports. Select auditors When the laboratory initializes an internal audit programme, selection of auditors is one of the first steps to address. It is very important, and required by ISO standards, that the auditors are independent of the area audited. Some things to consider are:  The availability of staffing and level of technical expertise—depending on the area for auditing, there might be many kinds of personnel who would be appropriate for conducting the audit; for example, if the laboratory is looking at safety issues, a hospital safety expert, or even a housekeeping expert might be appropriate.  Whether to hire a consultant—this could still be conducted as an internal audit: the audit is planned by the laboratory itself, without any external constraints, but consultants or peers recruited by the laboratory for this specific audit will help the laboratory staff to conduct it. Any knowledgeable person in the laboratory can perform internal audits, not just the manager or supervisor. Important skills for auditors When deciding the personnel to choose for the audit process, take into account the skills that will be needed for a good result. A good auditor will:  pay attention to details—for example, check expiry dates, open and inspect refrigerators and storage areas;  be able to communicate effectively, but also diplomatically—diplomacy is an important skill, since it is easy to imply criticism during an audit process. The auditors chosen must have the technical skills needed to evaluate the area being audited, and must have a good understanding of the laboratory’s quality management system. Some staff may have specialized expertise in a limited area, such as sample transport or housekeeping, but could serve as auditors in these areas. Some in-house training on how to conduct an audit should be provided to those who will serve as auditors. If auditors are poorly chosen, the audits will be much less effective. Laboratory Quality Management System 107  9-5: Actions as a result of audit Audits should Audits should lead to actions—this is why laboratories conduct them, to further lead to actions the process of continual improvement in the laboratory. Audits identify opportunities for improvement (OFIs). Both preventive and corrective actions are steps taken to improve a process or to correct a problem. A record of OFIs should be kept, along with actions that are taken. Preventive and corrective actions should be carried out within an agreed-upon time. Normally the quality manager is responsible for initiating actions. Problem Sometimes the cause of the problem is not obvious or easily found; in such cases solving a problem-solving team may be necessary to:  look for root causes;  recommend the appropriate corrective action;  implement the actions decided upon;  check to see if the corrective actions are effective;  monitor the procedures over time. All actions and findings from the monitoring should be recorded so the laboratory can learn from its activities. Continuous Continuous monitoring is the key monitoring element to success in the quality system. It is through this process that we are able to achieve the continual improvement that is our overall goal. Monitoring and evaluation Quality customer satisfaction improvement quality control plan proficiency testing audit Continuous quality improvement Corrective action 108 Laboratory Quality Management System  9-6: Summary Summary Assessment is important in monitoring the effectiveness of the laboratory quality management system. Both external and internal audits yield useful information. Audits are used to identify problems in the laboratory, in order to improve processes and procedures. An outcome of assessment is finding root causes of problems and taking corrective actions. Key  All laboratories should establish an internal audit programme. Conducted on a messages regular basis, it will provide information for continual improvement.  Problems become opportunities for improvement. Laboratory Quality Management System 109 10. Assessment— external quality assessment  10-1: Overview Role in quality Assessment is a critical aspect of management laboratory quality management, and Organization Personnel Equipment system it can be conducted in several ways. One of the commonly employed assessment methods is that of external quality assessment (EQA). Purchasing Process Information and control management inventory Documents Occurrence and Assessment management records Facilities Process Customer and improvement service safety Definition of The term EQA is used to describe a method that allows for comparison of EQA a laboratory’s testing to a source outside the laboratory. This comparison can be made to the performance of a peer group of laboratories or to the performance of a reference laboratory. The term EQA is sometimes used interchangeably with proficiency testing; however, EQA can also be carried out using other processes. EQA is here defined as a system for objectively checking the laboratory’s performance using an external agency or facility. Types of EQA Several EQA methods or processes are commonly used. These include: 1. Proficiency testing—external provider sends unknown samples for testing to a set of laboratories, and the results of all laboratories are analyzed, compared and reported to the laboratories. 2. Rechecking or retesting—slides that have been read are rechecked by a reference laboratory; samples that have been analyzed are retested, allowing for interlaboratory comparison. 3. On-site evaluation—usually done when it is difficult to conduct traditional proficiency testing or to use the rechecking/retesting method. Another method of interlaboratory comparison is the exchange of samples among a set of laboratories, usually reserved for specialized tests for which no proficiency testing is available. This method is used by very specialized or sophisticated laboratories and therefor