DefinitionThe lactate dehydrogenase (LDH) test measures the amount of LDH in the blood.See also: LDH isoenzymesAlternative NamesLDH test; Lactic acid dehydrogenase testHow the test is performedThe health care provider will take blood from a vein or from your heel, finger, toe, or earlobe.The blood sample is sent to a laboratory, where it is placed in a machine called a centrifuge. The machine quickly spins the blood, which causes the liquid part (the serum) to separate from the cells. The LDH measurement is done on the serum.How to prepare for the testYour health care provider may ask you to stop taking drugs that may affect the test. Drugs that can increase LDH measurements include anesthetics, aspirin, clofibrate, fluorides, mithramycin, narcotics, and procainamide.Why the test is perfor