1. Unit #5D – Clinical Laboratory Testing – Basic Clinical Chemistry
Cecile Sanders, M.Ed., MLS(ASCP)

2. Unit #5D – Clinical Laboratory Testing - Basic Clinical Chemistry
Purpose of Clinical Chemistry Tests
Measure levels of substances found normally in human blood that have biological functions. Examples: Glucose, Calcium
Detect or measure non-functional metabolites or waste products. Examples: Creatinine, Blood Urea Nitrogen (BUN)

3. Unit #5D – Clinical Laboratory Testing - Basic Clinical Chemistry
Detect or measure substances that indicate cell damage or disease. Examples: Liver enzymes, such as ALT, Cardiac enzymes, such as CK-MB
Detect or measure drugs or toxic substances. Examples: Dilantin, Drugs of abuse screen

4. Unit #5D – Clinical Laboratory Testing - Basic Clinical Chemistry
Types of Specimens for Chemical Analysis
Whole blood, serum or plasma. The most common specimen is serum, collected in a tube with no anticoagulant so that the blood will clot.
Urine – often 24 hour collections
Others – Cerebrospinal Spinal Fluid (CSF) and other fluids

5. Unit #5D – Clinical Laboratory Testing - Basic Clinical Chemistry
Blood to which an anticoagulant has been added will not clot. Blood cells will settle to the bottom of the tube leaving plasma at the top of the tube.

6. Unit #5D – Clinical Laboratory Testing - Basic Clinical Chemistry
Blood to which no anticoagulant has been added will clot. Blood cells get caught in the clot leaving serum behind.

7. Unit #5D – Clinical Laboratory Testing - Basic Clinical Chemistry
Collection and Handling of Blood Specimens for Chemical Analysis
Blood collection tubes for obtaining serum - Serum Separator Tubes (SST) do not have an anticoagulant but do contain a gel substance which will form an interface between the clot and the serum when the blood specimen is centrifuged. These tubes are sometimes referred to as “Tiger Tops”.

8. Unit #5D – Clinical Laboratory Testing - Basic Clinical Chemistry
Serum is separated from an SST (Tiger Top) tube

9. Unit #5D – Clinical Laboratory Testing - Basic Clinical Chemistry

10. Unit #5D – Clinical Laboratory Testing - Basic Clinical Chemistry
Blood collection tubes for obtaining plasma

11. Unit #5D – Clinical Laboratory Testing - Basic Clinical Chemistry
Patient preparation; time of collection; & effects of eating on chemistry analysis
Some specimens are increased or decreased after eating (ex. Glucose, triglycerides), so it is important to know what the test and collection method call for. Specimens for these tests are usually collected in a fasting state.

12. Unit #5D – Clinical Laboratory Testing - Basic Clinical Chemistry
Sometimes serum or plasma appears lipemia (milky) after a patient has eaten a fatty meal. Lipemia affects most chemistry analyses. The blood must be recollected when the patient is fasting.

13. Unit #5D – Clinical Laboratory Testing - Basic Clinical Chemistry
Clinical Chemistry Tests
Normal or Reference Values – range of values for a particular chemistry test from healthy individuals
Chemistry Panel grouping – some tests are “bundled” according to the system or organ targeted. Examples: thyroid panel, liver panel, cardiac panel, kidney panel, basic metabolic panel, etc.

14. Unit #5D – Clinical Laboratory Testing - Basic Clinical Chemistry
Commonly Performed Chemistry Tests or Analytes
Proteins – essential components of cells and body fluids. Some made by body, others acquired from diet. Provides information about state of hydration, nutrition and liver function, since most serum proteins are made in the liver.

15. Unit #5D – Clinical Laboratory Testing - Basic Clinical Chemistry
Electrolytes – sometimes called “lytes”
Includes sodium (Na), potassium (K), chloride (Cl) and bicarbonate (HCO3-)
Collectively these have a great effect on hydration, acid-base balance and osmotic pressure as well as pH and heart and muscle contraction
Levels differ depending on if inside vs. outside cells
Important in transport of substances into and out of cells

16. Unit #5D – Clinical Laboratory Testing - Basic Clinical Chemistry
Minerals
Calcium
Used in coagulation and muscle contraction
99% is in skeleton and is not metabolically active
Influenced by vitamin D, parathyroid hormone, estrogen and calcitonin
Hypercalcemia – occurs in parathyroidism, bone malignancies, hormone disorders, excessive vitamin D, and acidosis; may cause kidney stones
Hypocalcemia – can cause tetany; occurs in hypoparathyroidism, vitamin D deficiency, poor dietary absorption and kidney disease

17. Unit #5D – Clinical Laboratory Testing - Basic Clinical Chemistry
Phosphorus
80% in bone and rest in energy compounds such as ATP
Influenced by calcium and certain hormones
Iron
Essential for hemoglobin
Deficiency results in anemia; may be caused by lack of iron in diet, poor absorption, poor release of stored iron or loss due to bleeding
Increased in hemolytic anemia, increased iron intake or blocked synthesis of iron-containing compounds, such as in lead poisoning

18. Unit #5D – Clinical Laboratory Testing - Basic Clinical Chemistry
Kidney Function Tests
Serum Creatinine
Best test for overall kidney function; not affected by diet or hormone levels
Waste product of muscle metabolism
Serum creatinine rises when kidney function is impaired

19. Unit #5D – Clinical Laboratory Testing - Basic Clinical Chemistry
BUN (Blood Urea Nitrogen)
BUN is surplus amino acids that are converted to urea and excreted by kidneys as a waste product
BUN influenced by diet and hormones, so it is NOT as good an indicator of renal function as serum creatinine levels
BUN increased in kidney disease, high protein diet, and after administration of steroids
BUN decreased in starvation, pregnancy and in persons on a low protein diet

20. Unit #5D – Clinical Laboratory Testing - Basic Clinical Chemistry
Uric Acid
Formed from breakdown of nucleic acids and excreted as a waste product by kidneys
Increased in kidney disease, but most often used to diagnosis gout (pain in joints, mainly big toe, due to precipitated uric acid crystals)
Also increased in increased cell destruction, such as after massive radiation or chemotherapy

21. Unit #5D – Clinical Laboratory Testing - Basic Clinical Chemistry
Liver Function Tests
Liver functions:
Synthesizes glycogen from glucose
Makes plasma proteins (albumin, lipoproteins, coagulation proteins)
Forms cholesterol and degrades it into bile acids, which emulsifies fats for absorption
Stores iron, glycogen, vitamins and other substances
Destroys old blood cells and recycles components of hemoglobin

22. Unit #5D – Clinical Laboratory Testing - Basic Clinical Chemistry

23. Unit #5D – Clinical Laboratory Testing - Basic Clinical Chemistry
Total Bilirubin
Waste production of hemoglobin breakdown
Increased in excessive RBC breakdown, such as hemolytic anemia, or impaired liver function or some sort of obstruction, such as a tumor or gall stone

24. Unit #5D – Clinical Laboratory Testing - Basic Clinical Chemistry
Liver Enzymes – levels increase following damage to liver tissues
Alkaline Phosphatase (ALP or AP) - Greatly increased in liver tumors and lesions; moderately increased in diseases such as hepatitis
Alanine Aminotransferase (ALT; formerly called SGPT) - Increases up to 10x in cirrhosis, infections or tumors and up to 100x in viral or toxic hepatitis

25. Unit #5D – Clinical Laboratory Testing - Basic Clinical Chemistry
Asparate Aminotransferase (AST; formerly called SGOT) - Increased in liver disease, but also in heart attacks
Gamma Glutamyl Transferase (GGT) - Often used to monitor patients recovering from hepatitis and cirrhosis
Lactate Dehydrogenase (LD) - Increased in liver disease and following heart attacks

26. Unit #5D – Clinical Laboratory Testing - Basic Clinical Chemistry
Cardiac Function Tests
Creatine Kinase (CK) - Widely used to diagnosis and monitor heart attacks
Troponins
Only present in heart muscle, making it a more accurate indicator of heart attack than CK
Cardiac Troponin T (cTnT)
Cardiac Troponin I (cTnI)

27. Unit #5D – Clinical Laboratory Testing - Basic Clinical Chemistry
Lipid Metabolism Tests
Cholesterol
Present in all tissues
Serves as the skeleton for many hormones
Recommended to be less than 200 mg/dL in adults)
LDL = “bad” cholesterol; HDL = “good” cholesterol

28. Unit #5D – Clinical Laboratory Testing - Basic Clinical Chemistry
Triglycerides
Main storage form of lipids, comprising 95% of fat tissue
Hyperlipidemia – having high blood levels of triglycerides – may increase risk of heart attack
Carbohydrate Metabolism Tests
Glucose - Largely regulated by insulin

29. Unit #5D – Clinical Laboratory Testing - Basic Clinical Chemistry

30. Unit #5D – Clinical Laboratory Testing - Basic Clinical Chemistry
Thyroid Function Tests
Thyroid Stimulating Hormone (TSH) - Inverse relationship to thyroid function (the higher the TSH, the lower the thyroid function and vice versa)
Other less common thyroid tests include T3 and T4
Hypothyroidism – underactive thyroid gland
Hyperthyroidism – overactive thyroid gland

31. Unit #5D – Clinical Laboratory Testing - Basic Clinical Chemistry
For more information on most clinical laboratory tests, visit:
Click on any lab test or condition or disease and find all sorts of information!

32. Unit #5D – Clinical Laboratory Testing - Basic Clinical Chemistry
Photos of some clinical chemistry laboratories

33. Unit #5D – Clinical Laboratory Testing - Basic Clinical Chemistry
Basic Clinical Laboratory Techniques, Estridge and Reynolds, Thomson/Delmar Learning, Fifth Edition, 2008