What is a lactate dehydrogenase isoenzymes test?
Definition The enzyme lactate dehydrogenase (also known as lactic dehydrogenase, or LDH) is found in the cells of almost all body tissues. The enzyme is especially concentrated in the heart, liver, red blood cells, kidneys, muscles, brain, and lungs. The total LDH can be further separated into five components or fractions labeled by number: LDH-1, LDH-2, LDH-3, LDH-4, and LDH-5. Each of these fractions, called isoenzymes, is used mainly by a different set of cells or tissues in the body. For this reason, the relative amounts of a particular isoenzyme of LDH in the blood can provide valuable diagnostic information. Purpose The LDH isoenzymes test assists in differentiating heart attack, anemia, lung injury, or liver disease from other conditions that may cause the same symptoms (differential diagnosis). Precautions Strenuous exercise may raise levels of total LDH, specifically the isoenzymes LDH-1, LDH-2, and LDH-5. Alcohol, anesthetics, aspirin, narcotics, procainamide, fluorides, and
