LACTATE DEHYDROGENASE- LDH
Pre-test preparation or requirements
• Sample can be drawn at any time. No fasting or special preparation required.
• Blood sample should taken in plain vial. Can also be performed on other samples such as ascitic fluid.
230 -460 U/l
Significance of test
LDH is widely distributed in the body, high activities are found in the heart, liver, skeletal muscle, kidney, and erytrocytes, whereas lesser amounts are found in the lung, smooth muscle, and brain. Because of its widespread activities in numerous body tissues, LDH is elevated in a variety of disorders.
Disorders or conditions that can cause increased serum LDH activity:
Degenerative: hypoxia due to anemia or congestion and cholelithiasis
Metabolic: lipidosis or fat cow syndrome, diabetes mellitus, and equine hyperlipidemia
Neoplastic: lymphoma and metastatic neoplasia and hepatocellular carcinoma
-Infectious: bacterial and necrotic hepatitis, cholangiohepatitis, and hepatic abscess
-Noninfectious: Theiler's disease, chronic hepatitis, and cirrhosis
-Toxic: iron toxicity, alkaloid-containing plants, and aflatoxins
Muscle damage: skeletal or cardiac muscle (mostly skeletal)
Degenerative: hypoxia due to exertion or seizures, exertional rhabdomyolysis, and saddle thrombus
Metabolic and nutritional: feline hyperthyroidism and vitamin E or selenium deficiency
Neoplastic: metastatic neoplasia
Inherited: musculodystrophy and hyperkalemic myopathy
Inflammatory: myositis (Neospora and Toxoplasma), bacteria, or other agents
Toxic: monensin, castor bean, and gossypol
Traumatic: intramuscular injection, hit-by-car, recumbency, seizures, and exertion
Hemolysis (or prolonged serum contact with erythrocytes).
Ascitic fluid- LDH levels are high in malignant effusions and low in non-malignant effusions. The value of combining LDH with total protein analysis has been explored for ascitic fluid. The cut-off values for three parameters in the ascitic fluid for differentiation between hepatic and non-hepatic ascites are, as follows: LDH of 400 SU, fluid/serum LDH ratio of 0.6, and fluid/serum total protein (TP) ratio of 0.5. Ascitic levels higher than the cut-offs for any two out of three parameters indicate a non-hepatic cause of the ascites, whereas values below the cutoffs for all three parameters strongly suggest a hepatic cause of ascites.