Clinical Chemistry

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 mellitus 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:
    - Creatine kinase
    - Alanine aminotransferase (AAT, SGOT), aspartate or aminotransferase (AST, SGPT)
    - Amylase and lipase
  • Hormones are secreted by the various endocrine glands. Raised or lowered levels of certain hormones can indicate over- or under-activity of those glands:
    - Cortisol
    - Thyroxine (T4), TSH
    - FSH, ACTH, growth hormones
  • 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:
    - Cholesterol
    - High-density lipoprotein (HDL or "good" cholesterol)
    - Low-density lipoprotein cholesterol (LDL or "bad" cholesterol)
    - Triglycerides
  • Other metabolic substances can be measured to evaluate organ function:
    - BUN (blood urea nitrogen)
    - Uric acid
  • Proteins can indicate metabolic and nutritional disorders, as well as certain cancers:
    - Albumin
    - Globulins