Alanine Aminotransferase (ALT/SGPT)

Alanine Aminotransferase (ALT/SGPT)

CPT Test code: 84460

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Specimen: Serum (preferred) or plasma
Volume: 1 mL
Minimum Volume: 0.5 mL
Container: Red-top tube, gel-barrier tube, green-top (heparin) tube, or lavender-top (EDTA) tube
Collection: Separate serum or plasma from cells within 45 minutes of collection.
Storage Instructions: Maintain specimen at room temperature.
Causes for Rejection: Gross hemolysis; excessive lipemia; improper labeling
Use: 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.
Limitations: 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.
Additional Information: 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
Footnotes: 1. “Diagnosis and Treatment of Reye’s Syndrome,” JAMA, 1981, 246(21):2441-4. PubMed 7299966

2. Frank BB, Members of the Patient Care Committee of the American Gastroenterological Association, “Clinical Evaluation of Jaundice − A Guideline of the Patient Care Committee of the American Gastroenterological Association,” JAMA, 1989, 262(21):3031-4. 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, 100(5):646-50. 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, 61(4):754-7. PubMed 3422177

5. Seeff LB, Cuccherini BA, Zimmerman HJ, et al, “Acetaminophen Hepatotoxicity in Alcoholics. A Therapeutic Misadventure,” Ann Intern Med, 1986, 104(3):399-404. PubMed 3511825

6. Ulrich PP, Romeo JM, Lane PK, et al, “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, 86(5):1609-14.PubMed 2173725

References: Tonks DB, “A Study of the Accuracy and Precision of Clinical Chemistry Determinations in 170 Canadian Laboratories,” Clin Chem, 1963, 9:217-63.PubMed 13985504