Lactate dehydrogenase is an enzyme that exists in the blood cells as well as in the cells of many parts of the body, such as the heart, lung, kidney, liver and skeletal muscle, according to MedlinePlus. It also exists in bacteria, states Lab Tests Online.
There are five types of lactose dehydrogenase. Each type is structurally different, and each is prevalent in different parts of the body, but all types are detectable in the blood, says MedlinePlus. A doctor may check a patient's lactate deydrogenase levels through either his blood or other bodily fluids, such as the cerebrospinal fluid, according to Lab Tests Online. A high level of lactose dehydrogenase is usually a sign of tissue damage, and it may indicate the presence of health conditions, such as anemia, infections, muscle injuries, liver disease or cancer.