Laboratory Tests for Evaluation of Hepatitis B
The comprehensive evaluation of hepatitis B requires HBsAg, anti-HBc (total and IgM), HBeAg/anti-HBe, HBV DNA quantification, liver function tests, complete blood count, and tests to rule out coinfections. 1
Initial Serologic Testing
- HBsAg (Hepatitis B surface antigen) - Primary marker for active HBV infection; positivity for >6 months defines chronic infection 1
- Anti-HBc total (Hepatitis B core antibody) - Indicates current or previous HBV infection 1
- Anti-HBc IgM - Indicates acute infection when positive; may be detected at low levels in chronic infection 1
- Anti-HBs (Hepatitis B surface antibody) - Indicates recovery from infection or successful vaccination 1
- HBeAg (Hepatitis B e antigen) - Marker of high viral replication 1
- Anti-HBe (Hepatitis B e antibody) - Usually indicates lower viral replication when HBeAg becomes negative 1
Virologic Testing
- HBV DNA quantification - Essential for assessing viral replication, disease activity, and treatment decisions 1
Liver Function Tests
- ALT/AST (alanine and aspartate aminotransferases) - Assess liver inflammation 1
- Alkaline phosphatase and gamma-glutamyl transpeptidase - Additional markers of liver injury 1
- Bilirubin (total and direct) - Evaluates liver function 1
- Albumin - Assesses synthetic liver function 1
- Prothrombin time/INR - Evaluates coagulation and liver synthetic function 1
- Complete blood count with platelets - Low platelets may indicate portal hypertension 1
Tests for Coinfections
- Anti-HCV (Hepatitis C virus antibody) - Rules out HCV coinfection 1
- Anti-HDV (Hepatitis D virus antibody) - Important in patients with history of injection drug use or from endemic areas 1
- Anti-HIV - Recommended for those in high-risk groups 1
- Anti-HAV IgG - To determine immunity status to hepatitis A; vaccination recommended if negative 1
Additional Testing
- Alpha-fetoprotein (AFP) - Baseline screening for hepatocellular carcinoma 1
- Ultrasound - Recommended for baseline evaluation in high-risk patients 1
- Liver biopsy or non-invasive fibrosis assessment (e.g., transient elastography) - To evaluate inflammation and fibrosis when indicated 1
Interpretation of Common Serologic Patterns
- Acute HBV infection: HBsAg positive, IgM anti-HBc positive 1
- Chronic HBV infection: HBsAg positive for >6 months, total anti-HBc positive, IgM anti-HBc negative 1
- Past HBV infection with immunity: HBsAg negative, anti-HBs positive, total anti-HBc positive 1
- Vaccine-induced immunity: HBsAg negative, anti-HBs positive, total anti-HBc negative 1
- Isolated anti-HBc: HBsAg negative, anti-HBs negative, total anti-HBc positive - May represent resolved infection with waning anti-HBs, occult HBV infection, or false positive 1
Monitoring Recommendations
- For untreated patients with chronic HBV: ALT every 3-6 months, HBV DNA every 6-12 months, and HBeAg/anti-HBe status annually 1, 2
- For patients on treatment: ALT, HBV DNA, and other markers at regular intervals to assess response 1
- For cirrhotic patients: More frequent monitoring and surveillance for HCC with ultrasound every 6 months 1, 2
Common Pitfalls
- Failure to recognize the "window period" when both HBsAg and anti-HBs may be negative (IgM anti-HBc is positive during this period) 1
- Misinterpreting isolated anti-HBc positivity (requires follow-up testing) 1
- Not recognizing that HBeAg-negative chronic hepatitis B can have lower HBV DNA levels but still cause progressive liver disease 1
- Overlooking the need for coinfection testing, particularly in high-risk populations 1