Unit 4 Clinical Chemistry_Diane Perry 1.0.ppt
Transcript
1 CLINICAL CHEMISTRY The study of the chemical components of body 2.1.1,2.3,4.1, 6.1.7 OBJECTIVES CLINICAL CHEMISTRY 3 Objectives 1.Specimens in chemistry 1.1 List the differ...
1 CLINICAL CHEMISTRY The study of the chemical components of body 2.1.1,2.3,4.1, 6.1.7 OBJECTIVES CLINICAL CHEMISTRY 3 Objectives 1.Specimens in chemistry 1.1 List the different type of specimens 2. Basic tests in chemistry 2.1 List some of the common tests done in chemistry 3. Basic Principle in Chemistry 3.1 Describe the basic principle in chemistry 3.2 Explain the basic procedure in automated analysis 4 Objectives 4.0. Glucose testing 4.1 Define glucose 4.2 List the tests to diagnosis diabetes 4.3 Describe the step-by-step procedures for the following; - Random blood glucose - Fasting blood glucose - 2 hr. PC blood glucose - Non - Gestational Oral Glucose Tolerance test - 50 gm glucose challenge - Gestational Oral Glucose Tolerance test 5 Objectives 5. Hgb A1C 5.1 Define Hgb A1C 5.2 Explain how often this test is done 5.3 Describe which tube this test is collected 6. Electrolytes 6.1 Define electrolytes 6.2 List the type of electrolytes 6.3 List the 4 most common electrolytes 6.4 Describe some problems that might affect potassium level 6 Objectives 7. Renal function 7.1 List the tests used for diagnosing renal function problems 8. Lipids 8.1 Describe lipids and its function 8.2 List the tests used for assessing lipid metabolism 7 Objectives 9. Cardiac Disease - Myocardial Injury 9.1 Define cardiac disease 9.2 Define myocardial injury 9.3 Describe in detail the tests used for assessing cardiac disease - myocardial injury 10. Liver tests 10.1 Define what are liver tests 10.2 List the tests used for assessing 8 Objectives 11. Enzymes 11.1 Define an enzyme 12. Pancreatic testing 12.1 List some of common pancreatic tests 13. Hormone testing 13.1 Define a hormone 13.2 List some hormone tests 9 Objectives 14. Protein 14.1 Define what is a protein 14.2 Describe the different types of proteins 14.3 List some of common protein tests 15. Other Tests 15.1 List some other common test done in chemistry 16. Therapeutic Drug Monitoring 16.1 Describe the reason for therapeutic drug monitoring 16.2 Describe the procedure in therapeutic drug monitoring 10 Objectives 17. Trace Metals 17.1 Define trace metals 17.2 Describe which tube this test is collected 17.3 List some of the most common trace metals 18.0 Point of Care Testing ( POCT) 18.1 Define point of care testing ( POCT) 18.2 List some advantages using point of care testing 18.3 List some disadvantages using point of care testing 18.4 List some preanalytical errors 18.5 Describe the quality control in point of care testing 18.6 List some point of care testing machines 11 Objectives 19 Hemolysis 19.1 Define hemolysis 19.2 list the effects of hemolysis on chemistry results 12 Clinical chemistry Clinical chemistry is a branch of laboratory medicine that focuses on the analysis of bodily fluids, such as blood, urine, and other biological samples, to aid in the diagnosis, prognosis, and monitoring of disease and health conditions. 13 Clinical chemistry The clinical chemistry department of a laboratory is usually divided into three groups 1. Routine Chemistry 2. Routine Chemistry Urinalysis 3. Special Chemistry 14 Types of Specimens Blood ( serum or plasma) Urine Feces CSF Sweat hair 15 Clinical Chemistry Testing Clinical chemistry testing includes processes used to detect levels of enzymes, sugars, protein and other substances in the blood in order to determine such clinical conditions as nutritional state, liver function, kidney function and others Such testing is used to diagnose conditions such as diabetes, hyperlipemia, and arteriolosclerosis 16 Automation Chemistry was the first department to be automated There are many benefits for automation: They are: - Reduce of medical errors - Reduce specimen sample volume - Improve safety for staff ( Such as stopper piecing) - Faster Turn around time 17 Steps in Automated Analysis Step 1: Specimen collection and processing Step 2: Specimen and reagent measurement and delivery Step 3 : Chemical reaction phase Step 4 : Measurement phase Step 5 : Data handling 18 Steps in Automated Analysis Step 1 : Make sure that specimen is proper collected Step 2 :The instrument is programed to measure the proper amount od specimen and reagent to yield a final concentration 19 Steps in Automated Analysis Step 3 Most the automation is based on Photometry. Usually, a specimen is introduced into the instrument by a sample probe. This sample then travels through tubing and is mixed with various reagents in order to have a chemical reaction This chemical reaction causes the sample to change color. 20 Automated Analysis The sample then travels through a spectrophotometer. This part of the instrument measures how much light will pass through the sample. If the reaction has resulted in a dark color, less light will pass through = high result If the reaction has resulted in a lighter color, more light will pass through =lower result 21 Example Blood glucose will produce a blue color after chemical reaction with a reagent Dark blue = high glucose result Medium blue = normal glucose result Light blue = low glucose result The amount of color is determined by how much light passes through the sample. 22 Steps in Automated Analysis Step 4 The instrument is programed to measure the absorbance and give a result. Step 5 Reading the results and see if it falls within certain parameters. If it does not fall in these parameters, then step have to be taken. 23 Olympus Chemistry Analyzer AU5400 Series 6,600 tests per hour 24 Roche Clinical Chemistry Analyzer Model CA-270 270 tests/hour 25 TYPES OF INSTRUMENTS 26 Spectrophotometer A spectrophotometer is a scientific instrument used to measure the intensity of light at different wavelengths. Spectrophotometers work by passing a light beam through a sample and measuring how much of the light is absorbed or transmitted at each wavelength. This information can be used to determine the concentration of substances in the sample, as different substances absorb light differently at different wavelengths. 27 Spectrophotometer 28 Fluorometer A fluorometer is a scientific instrument used to measure the intensity and wavelength distribution of fluorescence emitted by a sample. Fluorescence is the process by which certain substances absorb light at a particular wavelength and re-emit light at a longer wavelength.. The basic principle of a fluorometer involves directing a specific wavelength of light onto a sample, causing the sample molecules to become excited and emit fluorescence. The emitted fluorescence is then detected by the instrument, and the intensity and wavelength characteristics are measured and analyzed. 29 Fluorometer 30 Osmometers Osmometers are used for determining the osmolarity of biological fluids and solutions. The osmolarity of a solution refers to the concentration of solute particles per unit volume of solvent. 31 Osmometers 32 COMMON TESTS DONE IN CLINICAL CHEMISTRY 33 Common tests done in clinical chemistry Bilirubin – formed by Hgb breakdown. Increased in liver damage. Urea – Urea nitrogen. Urea is the end product of protein metabolism and excreted by the kidneys. An increase may indicate kidney damage. Cholesterol & Triglyceride – measures the lipids in the body 34 Creatinine – metabolic waste. An increase indicates kidney damage Drug analysis – to determine the correct dosage of drug. Electrolytes – to test for electrolyte imbalance. Glucose – test for diabetes.( FBS, 2 hr PC, 1 hr post load, GTT, Hgb A1C) Hormones Troponin Creatine kinases LDH AST 35 GLUCOSE 36 Glucose is a simple sugar formed when dietary carbohydrates are digested. Is absorbed from the digestive tract into the blood. The liver removes excess glucose from the blood and stores it as glycogen When glucose is needed for energy by the body cells, the liver converts glycogen back to glucose ( glycogenolysis) 37 Glucose There are several different tests used to diagnosis and monitor diabetes - Random glucose - Fasting Blood glucose ( FBS) - 2 hour pc - 1 hour post load - Oral Glucose Tolerance test( OGTT, GTT) - HbA1c 38 Random Blood Glucose This test is taken any time There are no requirements 39 Fasting Blood Glucose Patient is instructed to fast for 8 – 12 hours Nothing to eat or drink during that time, except water. Normal FBS is 3.9 – 6.1 mmol/L 40 2-hour postprandial blood glucose test 2 hour PC- patient is instructed to have a substantial meal with a good amount of carbohydrates. The glucose is tested exactly 2 hours after the end of the meal. 41 2-hour postprandial blood glucose test ( 2 hr PC) This test is taken exactly 2 hrs after a meal Usually times are 1000 hrs, 1400hrs Normal 2 hr PC is 3.6-8.8 mmol/L 42 Screening for type 2 diabetes The fasting blood sugar is the usual method for screening for type 2 diabetes However when the fasting blood glucose is between 6.1 – 6.9 mmol/L. Other tests are done 43 There are 2 types of screening methods for diabetes Non - Gestational Oral Glucose Tolerance test Gestational Oral Glucose Tolerance test 44 Procedure of a OGTT (Non - Gestational ) 1) Patient is given instructions to fast for 8 – 12 hrs 2) Collect a venous fasting blood sample ( label the tube fasting) 45 3) A drink containing 75 gm of glucose is given to the patient. Must finish within 5 min - if the patient becomes sick, test is discontinued 4) Exactly 2 hrs after the drink has been consumed and venous blood sample is collected – label 2 h post load 46 Procedure to determine Gestational Diabetes Mellitus It is recommended that all pregnant women should be screened for diabetes between 24- 28 weeks It is a 2 step approach 47 Procedure to determine Gestational Diabetes Mellitus 1st step is called the 50 gm glucose challenge with a blood glucose level taken after 1 hr 48 50 gm glucose challenge Procedure 1) Patient does not have to fast 2) The patient is given 50 gms of glucose to drink. Must finish within 5 min. If the patient becomes sick the test is stopped 49 50 gm glucose challenge Procedure 3) Exactly 1 hr after consuming the drink, collect a blood sample. 4) Label 1 hour. 5) If the glucose level is between 7.8 – 11.0 mmol/L , then it is step 2 50 Procedure to determine Gestational Diabetes Mellitus Step 2 - This is done when the 1 hour 50 gm challenge glucose level is between 7.8 – 11.0 mmol/L 51 Procedure to determine Gestational Diabetes Mellitus This test is called Oral Glucose Tolerance Test (GTT) 52 Procedure of a GTT (Gestational ) 1) Patient is given instructions to fast for 8 – 16 hrs 2) A venous fasting blood sample is taken. ( label – fasting) 53 Procedure of a GTT (Gestational ) 3) A drink containing 75 gms of glucose is given to the patient. Must finish within 5 min - if the patient becomes sick, test is discontinued 54 Procedure of a GTT (Gestational ) 4) Exactly 1 hr after the drink has been consumed, take a venous blood sample. ( label 1 hour) 5) After another hour has passed, collect another venous blood sample ( label 2 hour) 55 Procedure of a GTT (Gestational ) Notes: - The patient cannot eat during the time of the test ( this includes gum, mints, etc) - No smoking - No excess walking during the test - If the patient become sick at any time, the test is discontinued. 56 Normal values for GTT Fasting 3.9-6.1mmol/L 1 hour 8.8-9.4 mmol/L 2 hours ≤ 6.6 mmol/L 3 hours 3.9-6.1 mmol/L 57 Hemoglobin A1C Definition: Hemoglobin A1C is a form of hemoglobin that is chemically linked with glucose molecules in the bloodstream. The A1C test measures the percentage of hemoglobin that has glucose attached to it. 58 Hemoglobin A1C This is a test used to determine the average blood glucose level in a patient over a 2 – 3 month period. Use EDTA Tube Very common test done on diabetics every 3 months Normal Hgb A1C = 4.4-6.4% 59 Hgb A1C 60 ELECTROLYTES 61 Electrolytes Electrolytes are essential minerals or ions that are present in bodily fluids and tissues, including blood, urine, and intracellular fluid. These ions carry an electrical charge and play critical roles in various physiological processes throughout the body. 62 Types of Electrolytes Types of Electrolytes: The main electrolytes in the human body include: Sodium (Na+) Potassium (K+) Chloride (Cl-) Calcium (Ca2+) Magnesium (Mg2+) Phosphate (PO43-) Bicarbonate (HCO3-) 63 Electrolytes There are 4 common electrolytes that medical practioners order: Sodium ( Na) – is responsible for the normal distribution of water between extracellular and intracellular compartments and also functions in transmission of nerve impulses Potassium ( K) – functions in muscle contractions, and conduction of nervous impulses 64 Chloride ( Cl) – functions to maintain water balance along with sodium Bicarbonate (HCO3-) – maintains the acid-base balance of the body ↑ CO2 =↓ PH of the blood Note: Make sure that Lithium heparin tubes are used for collection to prevent errors 65 Electrolytes Problems with Potassium( K) Because the concentration of K in RBC is about 20 times than in serum or plasma. It is important that hemolysis must be avoided. The following are some technical errors that can contribute to elevated K; - Recentrifugation of specimens in gel tubes. - Inadequate centrifugation - Delayed centrifugation - Poring blood from one tube to another - Improper venipuncture collection ( IV contamination) 66 RENAL FUNCTION 67 Renal function refers to the physiological processes carried out by the kidneys, which play a crucial role in maintaining overall health and homeostasis within the body. 68 Tests used for Renal Function - Urea - Creatinine - Uric Acid - Creatine Clearance - This test requires both - 24 hr. urine specimen and this test requires both a blood sample ( when the patient drops off the urine specimen) 69 LIPIDS 70 Lipids Lipids are a diverse group of organic molecules that are insoluble in water but soluble in organic solvents such as ether, chloroform, and benzene. They serve essential roles in cellular structure, energy storage, insulation, and signaling within the body. 71 Lipids Lipids play an important role in many metabolic processes. Lipids act as: - Hormone or hormone precursors - Energy storage and metabolic fuel - Structural and functional component in cell membrane - Insulation to allow conduction of nerve impulses or heat loss - There is a correlation between lipids and atherosclerosis ( which can lead to coronary heart disease) 72 Tests used for Lipids - Cholesterol - Triglycerides Low density lipoprotein ( LDL) High density lipoprotein ( HDL) 73 CARDIAC DISEASE - MYOCARDIAL INJURY 74 Cardiac Disease - Myocardial Injury Cardiac disease, particularly myocardial injury, refers to damage or impairment to the heart muscle (myocardium) due to various pathological processes. Myocardial injury can occur as a result of acute events such as myocardial infarction (heart attack). 75 Cardiac Disease - Myocardial Injury Today are 3 basic chemistry tests used to diagnosis a myocardial infarction or injury. - Myoglobin - Troponins - Creatine Kinase Myoglobin ( CK- MB) 76 Cardiac Disease - Myocardial Injury Myoglobin ( MB) - This heme protein is found in striated skeletal muscle and cardiac muscle. - MB is an early marker of injury to muscle tissue. - a rise in MB concentration can be detected in the blood as early as 1- 3 hours after the onset of MI symptoms 77 Cardiac Disease - Myocardial Injury Troponins - Cardiac troponins are the gold standard of cardiac markers. - Troponins is a complex of 3 proteins which are found in cardiac muscle or sketal muscle. They are; - Troponin T (TnT) - Troponin I ( TnI) - Troponin C ( Tnc) Troponins remain elevated in the blood for 4 – 10 days after MI 78 Cardiac Disease - Myocardial Injury Creatine Kinase Myoglobin ( CK- MB) CK-MB can be elevated after tissue injury Because CK-MB is cardio specific it is sensitive to early onset of MI Elevation can be seen within 4 – 6 hours of onset of symptoms 79 LIVER TESTS 80 Liver tests Liver tests, are a group of blood tests used to assess the health and function of the liver. These tests provide valuable information about liver enzymes, proteins, and other markers that can indicate liver damage, inflammation, or dysfunction. 81 Liver tests - Ammonia Bilirubin Alkaline phosphatase ( Alk phos) – bone, liver Gamma Glutamyl Transferase ( GGT)– Liver Alanine Transaminase ( ALT) – heart, liver Aspartate Transaminase ( AST)– heart, liver -Lactic Dehydrogenase ( LD) – liver, heart, muscle 82 Enzymes Note: Enzymes – accelerate many metabolic reactions in the body. The higher the number the more damage to the organ Enzymes usually end “ ase” 83 PANCREATIC TESTING 84 Pancreatic Testing Pancreatic testing involves a range of laboratory tests and imaging studies used to evaluate the structure and function of the pancreas, Pancreatic tests Lipase (LPS) – pancreas Amylase Isoamylase 85 HORMONES TESTS 86 Hormones Tests Hormone is defined as a chemical substance produced by a gland in one part of the body and carried to a distant target organ where a regulatory response is elicited. The chemistry dept. can measure most hormones 87 Hormones Tests Hormone tests are laboratory evaluations used to assess the levels of various hormones circulating in the bloodstream. Hormones are chemical messengers produced by endocrine glands and tissues throughout the body, playing essential roles in regulating physiological processes such as metabolism, growth and development, reproduction, stress response, and mood. 88 Examples of Hormone Tests Thyroid-Stimulating Hormone (TSH): Thyroxine (T4): Triiodothyronine (T3) Cortisol Adrenocorticotropic Hormone (ACTH): Follicle-Stimulating Hormone (FSH) Luteinizing Hormone (LH): Estradiol Testosterone: Progesterone 89 PROTEINS 90 Proteins Proteins are large, complex molecules made up of long chains of amino acids. They are essential macromolecules that play diverse and critical roles in the structure, function, and regulation of cells and tissues throughout the body. 91 Proteins The most prevalent type of protein is albumin – 2/3 of the total protein The other types are in a class called globulins Alpha 1 globulins Alpha 2 globulins Beta globulins Gamma globulins – most are antibodies 92 Gamma Globulins Are further divided into 5 groups IgA - respiratory, gut, skin, renal infections IgD chronic bacterial infections IgG – autoimmune responses IgE - asthma, allergic conditions IgM – viral infections, blood stream infections Decreased immunoglobulins are seen in immunodeficiency diseases 93 Protein Tests Albumin Total Protein Protein Electrophoresis – separates serum into 5 fractions - This is now done in Immunology 94 Protein Electrophoresis 95 OTHER TESTS 96 Other Tests Iron (FE)- test for anemia TIBC – for anemia Uric acid – a protein waste. Increased in gout, kidney disease, liver disease and hypertension. Calcium Phosphate Lactic Acid All types of drugs These are just a few of them. Look at the Lab Information manual 97 THERAPEUTIC DRUG MONITORING ( TDM) 98 Therapeutic Drug Monitoring ( TDM) Why do Therapeutic Drug Monitoring Helps to mange patients being treated with certain drugs in order to establish a drug dosage Adjust the dosage Identify non compliant patients Maintaining the dosage at a therapeutic level Avoid toxicity 99 Therapeutic Drug Monitoring ( TDM) There are 2 parts to TDM - Trough and Peak Trough level is taken before the drug is given 100 Therapeutic Drug Monitoring Peak are usually taken: 1)30 minutes after an IV administration 2)60 minutes after intramuscular injection 3)2 hrs. after oral intake 101 Therapeutic Drug Monitoring Examples of Drugs: - Digoxin Theophylline Vancomycin Phenytoin 102 TRACE METALS 103 Trace Metals Trace metals, also known as trace elements or microminerals, are essential minerals required by the body in very small amounts for various physiological processes. 104 Trace Metals Collected in a royal blue EDTA tubes Trace metals include: Aluminum Mercury Arsenic Selenium Cadmium Thallium Chromium Zinc Copper Lead Manganese 105 POINT OF CARE TESTING ( POCT) 106 Point of Care Testing ( POCT) This is testing done at the patient’s bed side or ancillary bedside, or near patient testing.( instead of in a lab) This bring the laboratory testing to the location if the patient Example of POCT is the glucometer. A glucometer is a device used to test blood sugar. It is commonly used by diabetics to monitor their blood sugar on a daily basis 107 Point of Care Testing ( POCT) Advantages of POCT - Small amount of blood - Rapid turn around time (TAT) - Easy to perform ( 1 or 2 steps) - Accuracy and precision comparable to central laboratory analyzers - Minimum QC tracking - Data can be interfaces with other LIS or other software 108 Point of Care Testing ( POCT) - Convince to the patient - Instead of going to the lab every time. The patient can do the testing at home. - Prompt medical attention - Quicker patient recovery - Improves access to healthcare services in rural locations - POC testing has been shown to decrease patient care costs 109 Point of Care Testing ( POCT) Disadvantage of POCT - Cost per test ( more expensive than central laboratory testing - Degree of maintance. For example : If glucometers are not cleaned properly between patient, can result in contracting a disease. - Also with improper cleaning the higher error rate with POCT than laboratory testing. 110 Point of Care Testing ( POCT) The most sources of POCT error are; Pre analytical errors operator incompetence, nonadherence to test procedures, and use of uncontrolled reagents and equipment 111 Point of Care Testing ( POCT) Infectious control issues To minimize the changes of fomites on POCT machines and patients, it is important to disinfect the POCT machines. Most manufactures recommend the use of 1: 10 bleach 1: 10 bleach has been proven effective,. 112 Point of Care Testing ( POC) Glucometers do one test. However there are POC machines that do more than on test. It all depends on the program or cartridge that is used. Some test include glucose and cholesterol levels, electrolytes and enzyme analysis, and cardiac markers. Also Hemoglobin , Hematocrit and INR. These are some of the tests. 113 An Example of Multiple Test POC Machine is the I - Stat 114 I - STAT 115 I – Stat Cartridge 116 I – STAT 117 i-STAT TEST CARTRIDGE MENU Sodium (Na) Potassium (K) Chloride (Cl) TCO2 Ionized Calcium (iCa) Glucose (Glu) Urea Nitrogren /Urea Creatinine (Crea) Lactate cTnI CK-MB β-hCG 118 POCT Quality Control Anyone who does POCT should be able to carry out quality control and maintenance procedures. 119 External quality control At one time external quality control had to be done everyday. Today external quality control is performed as per manufacturer guidelines. In most cases it means preforming liquid quality control on receipt of a new shipment of test kits and teaching new personnel. Also if the kits were not stored properly or if there is a question about the patients results. Then liquid quality control is also performed. 120 External quality control Liquid quality control is a liquid of a known result. The liquid is applied to the POCT instead of blood ( or other fluid). The result should read be exactly what the know result is. 121 Electronic QC’s Manufactures now have built electronic QC’S ( EQC’s) This means that the instrument can detect certain problems ; clotting, short samples air bubbles, etc, There are also internal checks that can determine if the instrument is functioning properly. Automatic lockout of users who are not authorized or do not adhere to QC procedures are a common software feature. 122 Quality Control All control result must be recorded on some type of document and reviewed for consistency and acceptability 123 124 Single testing Glucometer 125 Glucometer Drawing blood Prepare the lancing device by selecting the depth of penetration that will allow you to collect a drop of blood with the least amount of pain 126 Obtain the drop of blood by pressing the lancet device against the finger and pressing a button. Dispose of the used lancet by pressing the eject button on the device. Place the used lancet in a sharps container 127 Glucometer Testing Insert a test strip. The monitor will automatically turn on. The code number display must match the code number on the test strip container. Touch and hold the drop of blood to the edge of the sample area of the test strip until the sample area is filled. The glucose result will be displayed within a few seconds Discard the used test strip in a biohazard container 128 Hemoglobin A1C 129 Cholesterol Point of Care 130 Urinalysis 131 Pregnancy tests - Pregnancy test are a POCT - There are many different types of kits available( testing both serum and urine) - When using urine , there has to be suitable time after fertilization to allow B- HCG to rise to a significant level. - First morning specimen is required because it contain the highest concentration of the hormone. - Must be collected in a clean plastic container - It can be regrifrigated up to 2 days - Or frozen ( - 20 0 C) for 1 year. 132 Pregnancy tests 133 Multiple – Test – Panels by POCT There are several portable instruments ( some are handheld) that can measure multiple tests. Such as electrolytes urea, glucose, lactate hemoglobin These instruments are usually found in the ICU or ER These instrument play an important role in life threatening situations. 134 Multiple – Test – Panels by POCT 135 HEMOLYSIS 136 Hemolysis Hemolysis is the breakdown of red blood cells. This is important to the laboratory because it has an effect on lab results 137 Effects of hemolysis on Chemistry results Degree of change in Test result increased Test result decreased analyte by hemolysis by hemolysis Slight change Phosphate, total protein, Haptoglobin, bilirubin albumin, magnesium, Calcium, alk phos, Moderate change ALT, CK, Iron T4 Gross change K, LD, AST Troponin, glucose
