Glutamate Dehydrogenase (GD, GDH, GLDH)

Glutamate dehydrogenase is an indicator of damage to liver cells. It is a mitochondrial  leakage enzyme found in cytoplasm, and is more liver specific than AST. Generally, it is less sensitive than GGT for detecting liver damage in horses but has a better positive predictive value. The magnitude in serum increase generally correlates to the number of hepatocytes affected but cannot be used to assess prognosis. The half-life is approximately 14 hours in the bovine. Serum GDLH may sometimes increase with phenobarbital treatment.

The major differentials for increased GLDH include circulatory disturbances (including anaemia), hepatotoxicity, infection, inflammation, endocrine associated hepatopathy, neoplasia, and drug effects.


All, but most commonly used in large animals (horse, ruminants)


Plasma or Serum


Gel or plain tube

Collection protocol:

Fasted sample preferred (in companion animals).


Reference(s): Stockham, S.L and Scott, M.A. Fundamentals of Veterinary Clinical Pathology 2nd Edition 2008. Thrall M.A. Veterinary Hematology and Clinical Chemistry 2006