ALANINE AMINOTRANSFERASE (ALT) - plasma or serum

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Specimen: 5 mL blood in lithium heparin or plain tube.

Method: Spectrophotometry.

Reference Interval:

Adult:	<35 U/L
Neonate:	<50 U/L

Application: Detection and monitoring of liver cell damage.

Interpretation: Increased ALT levels are associated with hepatocellular damage. ALT is more specific for hepatocellular damage than is AST or LD and remains elevated for longer, due to its longer half-life. The AST/ALT ratio is typically >1 in alcoholic liver disease and <1 in non-alcoholic liver disease. ALT may be slightly elevated in skeletal muscle disease, but the degree of elevation is much less than for AST and CK.

Reference: Moss DW and Henderson AR. In: Burtis CA and Ashwood ER eds. Tietz Textbook of Clinical Chemistry. 2nd ed. WB Saunders 1994.

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