What is the sequence of Hepatitis B (HB) testing to rule out ongoing infection?

Hepatitis B Testing Sequence to Rule Out Ongoing Infection

The optimal testing sequence for ruling out ongoing hepatitis B virus (HBV) infection requires initial HBsAg testing, followed by anti-HBc and anti-HBs testing to determine infection status, with HBV DNA testing in specific scenarios. 1

Initial Testing Panel

The primary testing sequence should include:

1. Hepatitis B surface antigen (HBsAg): The first and most essential test to detect active infection
2. Antibody to hepatitis B core antigen (anti-HBc): Indicates previous or ongoing exposure to HBV
3. Antibody to hepatitis B surface antigen (anti-HBs): Indicates immunity from vaccination or resolved infection

Interpretation of Initial Testing Results

• HBsAg positive: Indicates active HBV infection (acute or chronic)

  • Chronic infection is confirmed if HBsAg persists for >6 months 1
  • Additional testing for HBeAg, anti-HBe, and HBV DNA should be performed to assess viral replication and disease activity

• HBsAg negative, anti-HBc positive, anti-HBs positive: Indicates resolved HBV infection with immunity 1

• HBsAg negative, anti-HBc negative, anti-HBs positive: Indicates successful vaccination 1

• HBsAg negative, anti-HBc positive, anti-HBs negative: Requires further evaluation as this may represent:

  • Resolved infection with waning anti-HBs levels
  • "Window period" of acute infection (confirm with IgM anti-HBc)
  • Occult HBV infection (consider HBV DNA testing) 1, 2

Additional Testing in Specific Scenarios

For Suspected Acute Infection

• IgM anti-HBc: Positive in acute infection and persists for up to 6 months
  • Note: IgM anti-HBc can sometimes be positive during flares of chronic infection 1

For Suspected Chronic Infection

• HBeAg and anti-HBe: Assess viral replication status

  • HBeAg positive: Generally indicates high viral replication
  • Anti-HBe positive: Usually indicates lower viral replication 1

• HBV DNA: Quantifies viral load to:

  • Confirm occult infection in HBsAg-negative, anti-HBc-positive patients
  • Assess disease activity and guide treatment decisions
  • Differentiate between inactive carrier state and HBeAg-negative chronic hepatitis B 1

For Suspected Occult Infection

• HBV DNA testing: Recommended for HBsAg-negative, anti-HBc-positive patients who are:
  • Immunocompromised or receiving immunosuppressive therapy
  • Undergoing chemotherapy
  • Donating blood or organs 2

Follow-up Testing

• For patients with initial positive HBsAg, repeat HBsAg testing after 6 months to differentiate between acute and chronic infection 1

• For patients with indeterminate results, repeat testing in 3-6 months 1

Important Considerations and Pitfalls

• Window period: During acute infection, there may be a period when HBsAg has disappeared but anti-HBs has not yet appeared. During this time, anti-HBc (particularly IgM anti-HBc) may be the only detectable marker 1

• Occult HBV infection: HBV DNA may be detectable in approximately 10% of HBsAg-negative/anti-HBc-positive patients 2, which has implications for transmission risk and clinical management

• False-positive results: Transient HBsAg positivity can occur for up to 18 days after hepatitis B vaccination and is clinically insignificant 1

• Co-infection testing: Consider testing for hepatitis A, C, D, and HIV in high-risk individuals 1

• Vaccination status: Always consider vaccination history when interpreting results, as vaccinated individuals will be anti-HBs positive but anti-HBc negative 1

By following this testing sequence, clinicians can accurately determine a patient's HBV infection status and provide appropriate management to prevent complications of chronic infection.