LDH isoenzymes is a test to check how much of the different types of lactate dehydrogenase (LDH) are in the blood. Measurement of LDH isoenzymes helps determine the location of any tissue damage. LDH is found in many body tissues such as the heart, liver, kidney, skeletal muscle, brain, blood cells, and lungs. LDH exists in 5 forms, which differ slightly in structure.
LDH-1 is found primarily in heart muscle and red blood cells.
LDH-2 is concentrated in white blood cells.
LDH-3 is highest in the lung.
LDH-4 is highest in the kidney, placenta, and pancreas.
LDH-5 is highest in the liver and skeletal muscle.