LDH (lactate dehydrogenase) is found in almost all tissues but only a small amount of it is detectable in the blood. It usually stays within the cells. When cells are damaged or destroyed, LDH enters the blood. LDH within a health screening is used as a general marker of injury to cells, and many cells can release it to varying degrees. A total LDH level is an overall measurement of five different LDH isoenzymes (or subgroups). A rise in the level may indicate a problem with cell damage somewhere in the body. A low level is probably of little significance.
Elevations in serum lactate dehydrogenase occur from myocardial infarction, liver disease, pernicious and megaloblastic anemia, pulmonary emboli, malignancies, and muscular dystrophy