Quality Assurance in Diagnostics
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Questions and Answers

What is the primary focus of quality assurance (QA)?

  • Preventing problems before they occur (correct)
  • Identifying errors after they occur
  • Correcting mistakes during the testing process
  • Monitoring results after testing

    • Quality control (QC) is a proactive method that ensures consistent high quality results.

    False (B)

    What term describes mistakes in writing results?

    Clerical Errors

    The organizational structure and responsibilities for implementing quality management in the lab is defined as a _____ system.

    <p>Quality</p> Signup and view all the answers

    Match the following terms with their definitions:

    <p>Pre-analytical = Before testing Analytical = Testing phase Post-analytical = After testing Accuracy = Closeness of result to true result</p> Signup and view all the answers

    What does a true positive (TP) result indicate in the context of diagnostic testing?

    <p>A positive test result for patients who have the disease (C)</p> Signup and view all the answers

    All diagnostic tests are able to detect all persons with a disease accurately.

    <p>False (B)</p> Signup and view all the answers

    In the context of test results, what is a false negative (FN)?

    <p>A negative test result for patients who do have the disease</p> Signup and view all the answers

    A higher _______ means that a negative test result is more likely to be correct (i.e., the person does not have the condition).

    <p>NPV</p> Signup and view all the answers

    In this example, how many people were incorrectly identified as diseased?

    <p>50 (A)</p> Signup and view all the answers

    A test can be 100% specific and 100% sensitive.

    <p>False (B)</p> Signup and view all the answers

    A higher _______ means that a positive test result is more likely to be correct (i.e., the person has the condition).

    <p>PPV</p> Signup and view all the answers

    Match the following results with their definition:

    <p>True positive (TP) = A positive test result for patients who have the disease True negative (TN) = A negative test result for patients who do not have the disease False positive (FP) = A positive test result for patients who do not have the disease False negative (FN) = A negative test result for patients who do have the disease</p> Signup and view all the answers

    What does a lower standard deviation (SD) indicate?

    <p>Higher precision (C)</p> Signup and view all the answers

    A higher standard deviation indicates higher precision.

    <p>False (B)</p> Signup and view all the answers

    What is the formula for calculating the coefficient of variation (%CV)?

    <p>(standard deviation x 100%) / mean</p> Signup and view all the answers

    Accuracy can be determined from the ______, which is the difference between the average of multiple measurements and the true value.

    <p>bias</p> Signup and view all the answers

    What are the purposes of clinical laboratory test results?

    <p>All of the above (D)</p> Signup and view all the answers

    Match the following terms with their corresponding definitions:

    <p>Reliability = Consistency of results Validity = Accuracy of measurement</p> Signup and view all the answers

    A test that consistently produces the same results each time it is administered is considered:

    <p>Reliable (B)</p> Signup and view all the answers

    What is the formula for calculating % accuracy error?

    <p>|True value-mean| / True Value x 100%</p> Signup and view all the answers

    Which of the following is a quantitative diagnostic test result?

    <p>WBC count (C)</p> Signup and view all the answers

    Accuracy refers to the reproducibility of results, while precision refers to the closeness to the true value.

    <p>False (B)</p> Signup and view all the answers

    A laboratory test for a patient's glucose level produces results of 95 mg/dL, 96 mg/dL, and 94 mg/dL. If the true value is known to be 100 mg/dL, is this data considered more accurate or more precise?

    <p>more precise</p> Signup and view all the answers

    The standard deviation is a direct measure of ______.

    <p>precision</p> Signup and view all the answers

    What is used to monitor the precision and accuracy of an assay?

    <p>Quality Control testing (D)</p> Signup and view all the answers

    A test is considered reliable if it maintains both precision and accuracy.

    <p>True (A)</p> Signup and view all the answers

    Match the terms with their definitions:

    <p>Accuracy = Closeness of the measured result to the true value Precision = Reproducibility or closeness of results to each other Reliability = Ability to maintain both precision and accuracy</p> Signup and view all the answers

    If a laboratory test yields results of 7.5, 7.6, and 7.4 mmol/L for a substance, and the true value is 5.0 mmol/L, would the results be considered accurate, precise or both?

    <p>precise only</p> Signup and view all the answers

    What are the three stages of analysis in the Quality Assurance Cycle?

    <p>Pre-analytic, Analytic, Post-analytic (D)</p> Signup and view all the answers

    External Quality Assessment (EQA) is only focused on internal processes without external evaluation.

    <p>False (B)</p> Signup and view all the answers

    What is the purpose of Internal Quality Assurance (IQA)?

    <p>To ensure well designed and implemented specimen collection and handling procedures.</p> Signup and view all the answers

    Quality Assurance helps prevent ______ and builds trust.

    <p>complaints</p> Signup and view all the answers

    Match the following components with their descriptions:

    <p>Internal Quality Assessment = Checking results through external agencies External Quality Assessment = Monitoring internal processes Standardization = Establishing consistent procedures across phases Quality Improvement = Enhancing overall lab efficiency</p> Signup and view all the answers

    Which of the following is a benefit of Quality Assurance?

    <p>Motivates staff (B)</p> Signup and view all the answers

    Pre-analytic errors include mistakes made during specimen collection and test ordering.

    <p>True (A)</p> Signup and view all the answers

    What are two potential errors that can occur during specimen collection?

    <p>Wrong tube and poor sample volume.</p> Signup and view all the answers

    Which of the following best defines quality assurance?

    <p>Development and implementation of measures to assure reliable laboratory service (A)</p> Signup and view all the answers

    Quality is defined solely by the cost of the product or service.

    <p>False (B)</p> Signup and view all the answers

    What are the two types of errors mentioned in clinical laboratories?

    <p>Clerical Errors and Analytical Errors</p> Signup and view all the answers

    The ability of a product or service to satisfy stated or implied needs is known as ______.

    <p>quality</p> Signup and view all the answers

    Match the following diagnostic indicators with their descriptions:

    <p>Sensitivity = The probability that a test correctly identifies a positive result Specificity = The probability that a test correctly identifies a negative result Test Efficiency = The overall accuracy of a diagnostic test Predictive Value = The likelihood that a positive or negative result is accurate</p> Signup and view all the answers

    Which of the following is NOT included in the basic components of a quality assurance program?

    <p>Performance appraisal (C)</p> Signup and view all the answers

    Predictive values indicate the effectiveness of a diagnostic test in identifying a condition.

    <p>True (A)</p> Signup and view all the answers

    What are the important terms in quality assurance that students should be able to list?

    <p>Accuracy, Precision, Sensitivity, Specificity, Test Efficiency, Predictive Values</p> Signup and view all the answers

    Flashcards

    Quality Assurance (QA)

    A proactive approach to prevent errors and ensure high-quality testing results.

    Quality Control (QC)

    A reactive method for monitoring and testing to identify deviations from quality standards.

    Pre-analytical Phase

    The stage referring to processes before testing begins.

    Accuracy

    The closeness of a test result to the true result.

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    Lab Quality System

    The structure and processes ensuring quality management in laboratory testing.

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    Importance of Quality Assurance

    Ensures the accuracy and reliability of laboratory tests and results.

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    Diagnostic Tests Classification

    Categorization based on type of result obtained and method of analysis.

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    Sensitivity

    The ability of a test to correctly identify those with the disease (true positive rate).

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    Specificity

    The ability of a test to correctly identify those without the disease (true negative rate).

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    Test Efficiency

    Measures the overall effectiveness of a diagnostic test based on true positive and true negative rates.

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    Predictive Values

    Indicate the likelihood that a test result reflects the true condition of a patient.

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    Errors in Clinical Laboratories

    Mistakes made in labs can be clerical, sampling, or analytical.

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    Standard Deviation (SD)

    A measure of variability indicating how spread out data points are around the mean.

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    Coefficient of Variation (CV)

    A standardized measure of the dispersion of a probability distribution, calculated as (SD/Mean) x 100%.

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    High Precision

    Indicated by low SD or CV, meaning data points are close to the mean.

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    Low Precision

    Indicated by high SD or CV, meaning there is greater variability in data points.

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    Bias

    The difference between the average of multiple measurements and the true value.

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    Accuracy Error (%)

    Calculated as |True Value - Mean| / True Value x 100%, should be < 5%.

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    Test Validity

    The ability of a test to accurately differentiate between disease presence and absence.

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    Reliability vs. Validity

    Reliability refers to consistency of results; validity refers to accuracy of what is measured.

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    Quality Assurance Cycle

    A systematic process to ensure quality in laboratory practices including preparation, collection, and reporting.

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    Internal Quality Assessment (IQA)

    An internal review of laboratory processes to ensure accurate and reliable results.

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    External Quality Assessment (EQA)

    An evaluation by an external agency to verify the lab's accuracy and performance.

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    Post-Analytic Phase

    Final stage focusing on reporting and data management after analysis.

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    Benefits of Quality Assurance

    Improves trust, reputation, and motivation while reducing complaints and costs.

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    Quality Control

    The routine processes to maintain standards in testing and ensure accuracy.

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    Specimen Collection Errors

    Potential mistakes including wrong specimens, incorrect ID, or inadequate samples.

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    Quantitative Diagnostic Test

    A test that provides numerical values with units.

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    Biochemical Results

    Data obtained from analyzing biological samples in laboratory tests.

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    Precision in Testing

    The reproducibility or closeness of test results to each other.

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    Accuracy in Testing

    The closeness of a measured result to the true value.

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    Reliability of Measurement

    The ability to maintain both precision and accuracy.

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    Standard Deviation

    A statistical measure used to quantify the precision of test results.

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    True Positive (TP)

    A positive test result for patients who have the disease.

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    True Negative (TN)

    A negative test result for patients who do not have the disease.

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    False Positive (FP)

    A positive test result for patients who do not have the disease.

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    False Negative (FN)

    A negative test result for patients who do have the disease.

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    Positive Predictive Value (PPV)

    PPV is the ratio of true positives to the sum of true positives and false positives.

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    Negative Predictive Value (NPV)

    NPV is the ratio of true negatives to the sum of true negatives and false negatives.

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    Four Test Outcomes

    The four outcomes are True Positive, True Negative, False Positive, and False Negative.

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    Screening Test Example

    In a sample of 1,000, results yield specific counts for TP, FP, TN, and FN.

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    Study Notes

    Learning Objectives

    • Students will be able to define quality assurance.
    • Students will be able to list important terms in quality assurance.
    • Students will be able to discuss the basic principles of quality assurance.
    • Students will be able to describe different components of quality assurance.
    • Students will be able to describe the importance and necessity of quality assurance.
    • Students will be able to classify types of diagnostic tests based on the type of result obtained and method of analysis.
    • Students will be able to describe accuracy and precision.
    • Students will be able to describe indicator values of diagnostic tests including sensitivity, specificity, test efficiency, predictive values.
    • Students will be able to calculate diagnostic values such as sensitivity, specificity, overall test efficiency, and predictive values.
    • Students will be able to use diagnostic values to determine the acceptability of test methods.

    Chapter Outline

    • Definition of important terms in quality assurance.
    • Essential components of quality systems.
    • Aspects of quality assurance.
    • Characteristics of quality assurance.
    • Basic components of quality assurance programs.
    • Benefits of quality assurance.
    • The purpose of a health laboratory.
    • Errors in clinical laboratories: clerical errors, sampling errors, analytical errors.
    • Types of diagnostic tests.
    • Accuracy and precision.
    • Indicators of values of diagnostic tests (sensitivity, specificity, test efficiency, predictive values).

    What is Quality Assurance?

    • Quality Assurance (QA) is the development and implementation of measures to ensure reliable laboratory service.

    What is Quality?

    • Quality is the ability of a product or service to satisfy stated or implied needs of a specific customer.
    • It's achieved by conforming to established requirements and standards.

    Quality Assurance vs. Quality Control

    • Quality Assurance (QA) is a proactive system designed to prevent errors for consistent high-quality results in testing processes.
    • Quality Control (QC) is a reactive method of monitoring and testing to identify and address deviations from quality standards. QA focuses on prevention while QC focuses on correcting.

    Definitions of Terms

    • Pre-analytic: activities related to specimen collection, transport, and handling (before testing)
    • Analytical: testing phase
    • Post-analytic: handling of results, reporting, and follow-up (after testing).
    • Clerical Errors: mistakes made in writing and recording test results.
    • Sampling errors: mistakes in collecting, handling or transporting specimen.
    • Accuracy: Closeness of a measured result to the true value.
    • Precision: Closeness of replicated measurements to each other.

    Definition of a Lab Quality System

    • The organizational structure, responsibilities, processes, procedures, and resources for implementing quality management in a laboratory.

    Why is the Quality System Important to Patient Sample Testing?

    • Quality systems ensure quality is fundamental to all activities.
    • It sets standards for quality, meets/exceeds customer expectations, and provides means to correct problems.
    • It also ensures monitoring, evaluation, and improvement systems.
    • A system for quality reduces costs.

    Essential Components of a Quality System

    • Organization: management organizational structure.
    • Personnel: human resource planning, hiring, training, supervision, performance management, retention
    • Equipment: selection, acquisition, initial calibration, maintenance, service and repair, troubleshooting, disposition.
    • Purchasing & Inventory: procurement, receiving, storage, inventory management, record keeping.
    • Processes & Control: standard operating procedures, specimen management, quality control.
    • Documents & Records: standardized forms, document approval, document distribution, document storage/retrieval, document destruction.
    • Information Management: Information flow, Data collection and management, Patient privacy and confidentiality, Computer skills.
    • Occurrence Management: written procedures for addressing errors, corrective actions, occurrence records, occurrence reporting.
    • Assessment: External quality assessment, Internal audit or self-evaluation, Improvement measures.
    • Process Improvement: on-going data collection, improvement measures.
    • Service & Satisfaction: monitoring customer satisfaction, process improvement, rewards.
    • Facilities & Safety: testing and storage areas, safety procedures and records.

    Quality System Organization

    • Quality Policy & Standards, Sufficient Resources, Clearly Defined Roles & Accountability, Culture Committed to Quality

    Quality System Personnel

    • Human Resource Planning, Hiring, Retentions, Training, Supervision, Performance Management

    Quality System Equipment

    • Selection, Acquisition, Installation & Initial Calibration, Maintenance, Service & Repair, Troubleshooting, Disposition

    Quality System Purchasing and Inventory

    • Procurement, Receiving, Storage, Inventory Management, Record Keeping

    Quality System Process Control

    • Standard Operating Procedures, Specimen Management, Quality Control

    Quality System Documents and Records

    • Standardized Forms, Document Approval, Document Distribution, Document Storage/Retrieval, Document Destruction

    Quality System: Information Management

    • Information Flow, Data Collection and Management, Patient Privacy & Confidentiality, Computer Skills

    Quality System: Occurrence Management

    • Written Procedures for Addressing Errors, Corrective Actions, Occurrence Records, Occurrence Reporting

    Quality System Essential Assessment

    • External Quality Assessment, Improvement Measures, Internal Audit or Self-Evaluation

    Quality System Process Improvement

    • On-Going Data Collection, Improvement Measures

    Quality System: Service and Satisfaction

    • Monitoring Customer Satisfaction, Process Improvement, Rewards

    Quality System Facilities and Safety

    • Testing and storage areas, safety procedures, safety records

    Total Quality Management

    • TQM addresses all areas of laboratory practice.
    • It includes lab services & resources.

    Purpose of Health Laboratory

    • Provide patient laboratory results.
    • Aid in diagnosis of disease
    • Help in determining prognosis.
    • Monitor the effects of treatment.
    • Monitor disease outbreaks.

    Characteristics and Aspects of Quality Assurance

    • Three phases affect useful patient results (pre-analytic, analytic, post-analytic).
    • Aspects of each phase are important for effective quality assurance.

    The Quality Assurance Cycle (diagram)

    • Pre-testing: Patient/client prep, sample collection, sample receipt, accessioning, & sample transport.
    • Testing phase: Testing, Quality control
    • Post-testing: Reporting, record keeping, Data and lab management, Safety.

    Basic Components of QA

    • Internal quality assessment (IQA).
    • External quality assessment (EQA).
    • Standardisation of processes.
    • Management and organisation.
    • Includes QC, EQA and quality improvement.

    CON... (Internal and External QA)

    • Internal QA involves implementing well-designed specimen-collection procedures.
    • External QA includes objective checks on lab results.

    Benefits of Quality Assurance

    • Help physicians, patients and clients.
    • Creates a good reputation.
    • Motivates staff.
    • Is cost-effective.
    • Prevents complaints.
    • Builds trust.

    Three Stages of Analysis

    • Pre-analytic
    • Analytic
    • Post-analytic
    • Errors in any stage can affect the system

    Pre-Analytic Errors

    • Test Ordering
    • Specimen Collection
    • Specimen Handling

    Pre-Analytic Specimen Collection Errors

    • Wrong Patient ID, Anticoagulant, Volume, Process, Hemolysis, IV contamination, Prolonged tourniquet

    Preventing and Detecting Errors - Before Testing

    • Check storage and room temperature
    • Select an appropriate testing workspace
    • Check inventory and expiration dates
    • Review testing procedures
    • Collect appropriate specimens

    Analytic Errors

    • Instrumental problems
    • Operator error
    • Reagent Issues
    • Methodological errors
    • Environmental factors

    Quality Assurance vs. Quality Control (table format)

    • Definition for both and comparison of Examples

    Quality Control Material

    • Assessing the analytic phase.
    • Acceptance versus rejection of patient results.
    • Includes 2 or 3 control materials.

    Westgard Rules

    • A set of statistical quality control guidelines for laboratories.
    • Used to monitor accuracy and precision of tests.

    Rules (1-3s, 2-2s, R-4s) (details)

    • Detailed explanation for each rules.

    Example calculation of Standard Deviation (SD)

    • Calculations used in example to explain SD.

    The standard deviation (SD)

    • Measure of variability or spread of data from the mean.
    • A lower SD indicates higher precision; higher SD indicates more variability/low precision.

    Precision Calculations (%CV)

    • Precision calculations using SD and %CV.

    Accuracy Calculations

    • Accuracy calculation methods using bias data.
    • Calculating % accuracy error

    Indicators of Diagnostic Tests

    • Clinicians depend on lab for accurate results.
    • Aid in diagnosis, patient prognosis, and treatment effectiveness assessment; determine relative risk of disease.

    Indicators of Diagnostic Tests and Medical Usefulness

    • Tests have inherent errors.
    • No test can detect all cases of disease or all cases without disease.
    • There may not be a test with 100% specificity and sensitivity.

    Four Possible Outcomes to Test Results and Disease Diagnosis

    • True Positive (TP)
    • True Negative (TN)
    • False Positive (FP)
    • False Negative (FN)

    Results of Disease Screening Testing: Possible Outcomes (table)

    • Table showing results of various screening testing

    Positive and Negative Predictive Values (PPV & NPV)

    • Explanation on how these values are calculated.
    • Higher values suggest better reliability in diagnosing patients

    Example: Screening Test (details)

    True Positives, False Positives, True Negatives, False Negatives

    • Explanation on these terms with an example

    Indicators of Diagnostic values of Test: Definitions

    • Sensitivity (calculated using True Positives and False Negatives)
    • Specificity (calculated using True Negatives and False Positives)

    Sensitivity/Specificity definitions based on diagnosis outcomes.

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    Related Documents

    Chapter 1: Introduction to Quality Assurance PDF

    Description

    This quiz focuses on the principles of quality assurance (QA) and quality control (QC) in diagnostic testing. Participants will learn the definitions and implications of key terms related to test results, such as true positives, false negatives, and accuracy in a lab setting. Challenge your understanding of QA processes and terminology.

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