What are the normal values for a hepatic (liver) panel?

Normal Values for Hepatic (Liver) Panel

The normal reference ranges for liver function tests include ALT <30 U/L for men and <19 U/L for women, AST <40 U/L, alkaline phosphatase <120 U/L, total bilirubin <1.0 mg/dL, and albumin 3.5-5.0 g/dL, according to the most recent guidelines. 1

Standard Components of a Hepatic Panel

A comprehensive hepatic panel typically includes:

• Alanine aminotransferase (ALT)

  • Men: <30 U/L
  • Women: <19 U/L
  • Note: Traditional upper limits (40 U/L for men, 30 U/L for women) may be too high 2

• Aspartate aminotransferase (AST)

  • <40 U/L

• Alkaline phosphatase (ALP)

  • Adults: 40-120 U/L
  • Note: Values <40 U/L are uncommon (0.25% of patients) 3

• Total bilirubin

  • <1.0 mg/dL

• Direct (conjugated) bilirubin

  • <0.3 mg/dL

• Albumin

  • 3.5-5.0 g/dL

• Gamma-glutamyl transferase (GGT)

  • Men: 8-61 U/L
  • Women: 5-36 U/L

Interpretation Patterns

Pattern Recognition

Liver test abnormalities can be categorized into patterns that help guide diagnosis 1:

1. Hepatocellular pattern:

   • Predominant elevation of aminotransferases (ALT, AST)
   • AST:ALT ratio <1 suggests viral hepatitis, NAFLD
   • AST:ALT ratio >2 suggests alcoholic liver disease
   • AST:ALT ratio >1 in non-alcoholic disease may suggest cirrhosis 4

2. Cholestatic pattern:

   • Predominant elevation of ALP and GGT
   • May indicate biliary obstruction or drug-induced liver injury

3. Mixed pattern:

   • Elevations in both aminotransferases and cholestatic markers

Clinical Significance and Monitoring

• The extent of liver test abnormality is not necessarily a guide to clinical significance 5
• Mild elevations (<5× upper limit of normal) are common and may be seen in NAFLD, which affects 20-30% of the general population 1
• Moderate elevations (5-10× ULN) warrant closer investigation
• Severe elevations (>10× ULN) may indicate acute hepatitis or drug-induced liver injury 1

Important Considerations

• ALP may originate from tissues other than the liver, most commonly from bone. Elevated ALP should be confirmed to be of hepatobiliary origin with GGT and/or ALP isoenzyme fractionation 5
• Laboratory reference ranges may vary between institutions
• The current upper limits of normal for liver enzymes (particularly ALT) may be too high due to inclusion of patients with subclinical liver disease in reference populations 2
• Liver enzymes should be monitored every 2-4 weeks until normalization in patients with abnormal values 1

Pitfalls to Avoid

• Don't assume that normal liver tests exclude significant liver disease - patients with cirrhosis or chronic hepatitis may have normal liver enzymes
• Don't rely solely on the magnitude of liver test abnormality to determine clinical significance
• Don't forget that medications can cause liver test abnormalities - a complete medication review should be performed when evaluating abnormal results 1
• Don't overlook the AST:ALT ratio, which can provide valuable diagnostic clues about the etiology of liver disease 4