Test Details: Lactate dehydrogenase (LDH) activity is present in all cells of the body with the highest concentrations in the heart, liver, muscle, kidney, lung and erythrocytes. LDH is normally present in blood & body fluids but elevated LDH level may indicate tissue damage. It is used in investigation of a variety of diseases involving the heart, liver, muscle, kidney, lung and blood. It is also used to monitor changes in tumor burden after chemotherapy.