What is the range of ALT (Alanine Transaminase) or AST (Aspartate Transaminase) levels that defines mild to moderate transaminitis?

Mild to Moderate Transaminitis: Definition and Ranges

Mild to moderate transaminitis is defined as ALT or AST elevations between 1-5× the upper limit of normal (ULN), with mild being 1-3× ULN and moderate being 3-5× ULN. 1, 2

Specific Ranges for Transaminitis

• Mild transaminitis: ALT/AST >1× to <3× ULN

  • Typically 40-135 IU/L (assuming ULN of ~45 IU/L)
  • Often asymptomatic and may be transient

• Moderate transaminitis: ALT/AST 3-5× ULN

  • Typically 135-225 IU/L (assuming ULN of ~45 IU/L)
  • Requires closer monitoring and evaluation

Clinical Context and Significance

• Most authorities in DILI (Drug-Induced Liver Injury) agree that mild asymptomatic increases in ALT/AST (>1× to <3× ULN) without elevated bilirubin are often non-specific 1

• Mild elevations may be related to:

  • Nonalcoholic fatty liver disease (NAFLD)
  • Changes in diet
  • Vigorous exercise
  • Medication effects 1, 3

• In patients with NAFLD, ALT values typically range between normal and 250 IU/L, usually <5× ULN 1

• Most central laboratories set the ULN for ALT around 40-45 IU/L 1

Management Approach Based on Severity

For Mild Transaminitis (1-3× ULN):

• If persistent but remains <3× ULN:
  • Implement lifestyle modifications
  • Monitor every 3 months 2
  • Consider causes like NAFLD, alcohol use, medications

For Moderate Transaminitis (3-5× ULN):

• More urgent evaluation for potential causes including:
  • Drug-induced liver injury
  • Viral hepatitis
  • Autoimmune hepatitis 2
• Consider referral to hepatology if persistent >6 months despite interventions 2

Important Considerations

• Transient elevations may spontaneously revert to baseline even with continued therapy (adaptation) 1
• The term "transaminitis" is often used clinically but some experts prefer more specific terminology like "elevated serum aminotransferases" 1
• ALT >5× ULN is considered marked elevation requiring more urgent evaluation 2

Common Pitfalls to Avoid

• Assuming normal enzymes exclude significant liver disease 2
• Simply repeating abnormal tests without investigating the cause 2
• Overlooking non-hepatic causes of enzyme elevation (muscle injury, thyroid disorders, celiac disease) 2
• Premature discontinuation of medications for mild, asymptomatic elevations 2

Remember that transaminase elevations >5× ULN or any elevation with increased bilirubin should prompt immediate evaluation, as these findings suggest more severe liver injury.