Clinical Chemistry
Clinical chemistry uses chemical processes to measure levels of chemical components in the blood. The most common specimens used in clinical chemistry are blood and urine. Many different tests exist to test for almost any type of chemical component in blood or urine. Components may include blood glucose, electrolytes, enzymes, hormones, lipids (fats), other metabolic substances, and proteins.
The following is a description of some of the most common clinical chemistry tests (used on blood and urine specimens), including some of the uses and indications:
- Blood glucose, or blood sugar, levels indicate how the body handles glucose. Measuring glucose levels after fasting can help diagnose diabetes or hypoglycemia (low blood sugar).
- Electrolytes may include sodium, potassium, chloride, bicarbonate, calcium, phosphorus, and magnesium. Measuring electrolytes can specifically indicate certain metabolic and kidney disorders.
- Enzymes are released into the blood by organs that are damaged or diseased. The type of enzyme released can indicate which organ is affected:
| Enzyme |
Organ Affected |
| Creatine kinase |
Can signal heart damage from heart attack or other |
| Alanine aminotransferase (AAT, SGOT), aspartate or aminotransferase (AST, SGPT) |
Can signal liver disorders and bone diseases |
| Amylase and lipase |
Can signal inflammation or cancer of the pancreas |
- Hormones are secreted by the various endocrine glands. Raised or lowered levels of certain hormones can indicate over- or under-activity of those glands:
| Hormone |
Gland Affected |
| Cortisol |
Adrenal Glands |
| Thyroxine (T4), TSH |
Thyroid Gland |
| FSH, ACTH, growth hormones |
Pituitary Gland |
- Lipids are fatty substances such as triglycerides (body fat), phospholipids (part of cell membranes), and sterols (such as cholesterol). Lipids can help signal coronary heart disease and liver disease:
| Lipid |
Organ Affected |
| Cholesterol |
Can signal coronary heart disease |
| High-density lipoprotein (HDL or "good" cholesterol)
Low-density lipoprotein (LDL or "bad" cholesterol)
|
Can estimate risk for coronary heart disease |
| Triglycerides |
Together with levels of cholesterol, this lipid can help indicate risk for coronary heart disease |
- Other metabolic substances can be measured to evaluate organ function:
| Metabolic Product |
Organ Affected |
| BUN (blood urea nitrogen) |
Kidney function |
| Uric acid |
Can signal gout, kidney disease, and other tissue damage |
- Proteins can indicate metabolic and nutritional disorders, as well as certain cancers:
| Protein |
Organ Affected |
| Albumin |
Can signal liver or kidney disease, or malnutrition |
| Globulins |
Can signal infection, inflammation, and certain blood cancers |
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