Chemistry Blood Tests - The Basics

The medical/hospital laboratory is divided into departments, such as Hematology, Microbiology, Blood Banking, and Chemistry. This article discusses typical Chemistry tests your doctor might order.

Chemistry tests can be ordered singly, such as glucose (blood sugar), or in groups called "panels." Different labs offer different panels. Typically, the following panels will be offered.

Liver panel-tests for a variety of liver enzymes. If the liver is damaged or diseased, the liver cells release their enzymes. If these enzyme levels are high in the blood, it indicates liver damage or disease. This panel screens for hepatitis, blocked bile duct, or liver function. It usually consists of protein, bilirubin, and the enzymes SGOT (also known as AST), SGPT (also known as ALT), and Alkaline Phosphatase.

Kidney panel--tests for kidney disease or damage. Consists of BUN (blood urea nitrogen) and creatinine and electrolytes. Tells the doctor if the kidney is functioning properly.

Cholesterol panel-consists of triglycerides (also known as fats or lipids), cholesterol, and two types of cholesterol called HDL and LDL. HDL is the "good" cholesterol and LDL is the "bad" cholesterol. You need to be fasting for this test.

Electrolyte panel-consists of sodium (Na), Chloride (Cl), Potassium (K), and carbon dioxide (CO2). Abnormal electrolyte levels can indicate a variety of problems such as dehydration or diseases such as Addison's or Cushing's.

Cardiac panel. This panel tests for heart damage. When the cardiac (heart) tissue is damaged, the cardiac cells release their enzymes, elevating the blood levels of those enzymes. The enzymes are called CPK, SGOT (AST) and LDH.

Comprehensive Metabolic Panel. Various labs offer different panels. They can have 6 tests, 12 tests, or 20 tests. The latter would run tests for various organ function such as kidney, liver, and heart, covering the entire body. Different labs will have different names for this panel.

FBS stands for Fasting Blood Sugar, which is the same as glucose. This test will be ordered separately, or in a panel. Tests for diabetes.

ABG stands for Arterial Blood Gas. The above tests are done on venous blood. A separate draw is needed for arterial blood, where a specially trained nurse, respiratory therapist, or lab tech will go into an artery to draw blood. This is a specialized draw which tests for the pH of the arterial blood, and the oxygen and carbon dioxide levels. Normal arterial blood pH is 7.38 to 7.42. A high pH may indicate a hyperventilator.