Alanine Aminotransferase (ALT / SGPT)

Overview:

A liver function test, ALT is more sensitive for the detection of hepatocyte injury than for biliary obstruction. ALT is more specific for liver injury than AST (SGOT). Useful for hepatic cirrhosis, other liver disease. Increased in Reye syndrome, with AST.1 Test for hepatitis. Acute hepatitis A or B can be confirmed serologically, as can hepatitis C. Negative serological findings in the presence of hepatitis-like chemistry abnormalities may also suggest acute drug-induced hepatitis, an impression supported by resolution after removal of the offending agent.2 The combination of increased AST and ALT with negative hepatitis markers occurs in a number of other entities including infectious mononucleosis. Sensitive to heart failure.

Grossly hemolyzed samples can generate somewhat spurious results. The activity in red cells is six times that of serum. Elevations are reported in trauma to striated muscle, rhabdomyolysis, polymyositis and dermatomyositis, but the CK (CK-MM fraction) is increased in such patients and it is preferable to consider diseases of skeletal muscle. ALT is less sensitive than is AST to alcoholic liver disease. Increased ALT is found with obesity.

Among entities in which AST and ALT increases occur, are therapeutic applications of bovine or porcine heparin. LD (LDH) abnormality with elevation of hepatic fractions was also reported.3 In children with acute lymphoblastic leukemia, high ALT activity at diagnosis is associated with rapidly progressive ALL.4 A number of drugs, including diphenylhydantoin, heparin therapy and many others, cause ALT increases. Acetaminophen hepatotoxicity may be potentiated in alcoholics, in whom coagulopathy and extremely abnormal aminotransferase levels are described, ALT less than AST.5 The hepatitis C virion has been detected by polymerase chain reaction and reverse transcriptase of HCV-RNA sequences in patients with elevated ALT and positive anti-HCV.6

1. Diagnosis and treatment of Reye's syndrome. JAMA. 1981 Nov 27; 246(21):2441-2444. PubMed 7299966

2. Frank BB. Clinical evaluation of jaundice. A guideline of the Patient Care Committee of the American Gastroenterological Association. JAMA. 1989 Dec 1; 262(21):3031-3034. PubMed 2681857

3. Dukes GE Jr, Sanders SW, Russo J Jr, et al. Transaminase elevations in patients receiving bovine or porcine heparin. Ann Intern Med. 1984 May; 100(5):646-650. PubMed 6712030

4. Rautonen J, Siimes MA. Elevated serum transaminase activity at diagnosis is associated with rapidly progressing disease in children with acute lymphoblastic leukemia. Cancer. 1988 Feb 15; 61(4):754-757. PubMed 3422177

5. Seeff LB, Cuccherini BA, Zimmerman HJ, Adler E, Benjamin SB. Acetaminophen hepatotoxicity in alcoholics. A therapeutic misadventure. Ann Intern Med. 1986 Mar; 104(3):399-404. PubMed 3511825

6. Ulrich PP, Romeo JM, Lane PK, Kelly I, Daniel LJ, Vyas GN. Detection, semiquantitation, and genetic variation in hepatitis C virus sequences amplified from the plasma of blood donors with elevated alanine aminotransferase. J Clin Invest. 1990 Nov; 86(5):1609-6914. PubMed 2173725 Tonks DB. A study of the accuracy and precision of clinical chemistry determinations in 170 Canadian laboratories. Clin Chem. 1963 Apr; 9:217-233. PubMed 13985504