Chemistry, Blood

Clinical Chemistry

What is clinical chemistry?

Clinical chemistry uses chemical processes to measure levels of chemical components in body fluids. 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.

What are some common clinical chemistry tests?

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 problem
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 risk for 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

Lipid

Organ affected

Cholesterol

Can signal risk for 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