II. Definition

  1. Serum transaminase most specific for hepatocyte injury

III. Normal

  1. Level <35 U/L

IV. Increased

  1. See Liver Function Test Abnormality
  2. Common causes based on degree of elevation
    1. Alcohol
      1. ALT rarely above 400
      2. AST more than twice ALT
    2. Transient biliary obstruction: Common Bile Duct Stone
      1. ALT may rise to 1000
      2. ALT rises rapidly and then quickly normalizes
    3. Autoimmune Hepatitis: ALT rises gradually to 1000
    4. Viral Hepatitis
      1. Most viruses: ALT rises gradually to 2000
      2. Atypicals (e.g. herpes): Rapid increase to 2000
    5. Medications:
      1. Most medications: ALT rises gradually to 1500
      2. Acetaminophin and toxins: Rises rapidly to >2000
  3. Common liver disease causes
    1. Alcohol Abuse
    2. Cirrhosis
    3. Chronic Hepatitis B
    4. Chronic Hepatitis C
    5. Acute Viral Hepatitis
      1. Hepatitis A
      2. Epstein Barr Virus (EBV)
    6. Hepatotoxins
    7. Steatohepatitis (Fatty Liver)
  4. Uncommon liver disease causes
    1. Autoimmune Hepatitis
    2. Hemochromatosis
    3. Alpha-1-Antitrypsin Deficiency
    4. Wilson's Disease
  5. Non-liver disease causes
    1. See Aspartate Transaminase (AST)
  6. Conditions with ratio of AST to ALT > 2
    1. Alcoholism
    2. Wilson's Disease (ratio may exceed 4)

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