Elevated LDH levels have been noted in several disease states, but expressed most extensively in musculoskeletal cells, renal, liver, cardiac tissue and red blood cells.

The most common causes for an acutely elevated LDH are cardiopulmonary failure, sepsis, shock and hepatocyte injury. High levels are also seen with megaloblastic anaemia, haemolysis, pernicious anaemia, malignancy of all types – metastatic disease or from tumour necrosis; muscular dystrophy and cirrhosis. LDH may rise following myocardial infarction and in myocarditis. It is a late marker of infarction, as levels increase 12 to 24 hours after onset of an MI, peaking at 48 – 72 hours. With some chronic and progressive conditions, moderately elevated LDH levels may persist.