What to do next if a patient is Hepatitis B surface antigen (HBsAg) positive?

Management of HBsAg Positive Patients

When a patient tests positive for Hepatitis B surface antigen (HBsAg), they should be referred for comprehensive evaluation including additional serologic testing, liver function assessment, and viral load quantification to determine disease status and guide appropriate management. 1

Initial Evaluation

Required Testing

• Complete hepatitis B panel:

  • HBsAg (already positive)
  • Anti-HBs (hepatitis B surface antibody)
  • HBeAg (hepatitis B e antigen) and anti-HBe
  • Anti-HBc (hepatitis B core antibody)
  • Quantitative HBV DNA level 2

• Liver function assessment:

  • ALT/AST and complete liver function tests
  • Complete blood count with platelets
  • Prothrombin time/INR
  • Renal function tests 2

• Fibrosis assessment:

  • Non-invasive fibrosis assessment (transient elastography/FibroScan or serum fibrosis markers)
  • Abdominal ultrasound to assess for cirrhosis and screen for hepatocellular carcinoma 2

• Coinfection screening:

  • HIV testing 1
  • Hepatitis C virus (HCV) antibodies
  • Hepatitis D virus (HDV) antibodies
  • Hepatitis A immunity 2

Confirmation of Chronic Infection

• A second HBsAg test should be performed at a different time point (at least 6 months apart) to confirm chronicity 1
• Chronic hepatitis B is defined by HBsAg positivity for more than 6 months 1

Patient Education and Contact Management

• Provide education about HBV transmission, disease progression, and treatment options 1
• Advise on limiting or avoiding alcohol consumption 1, 2
• Counsel on preventing transmission:
  • Notify household, sexual, and needle-sharing contacts for testing and vaccination
  • Use condoms with non-immune sexual partners
  • Cover cuts and skin lesions
  • Avoid sharing household items that could be contaminated with blood
  • Refrain from donating blood or organs 2
• Arrange contact follow-up including vaccination of susceptible contacts 1

Treatment Decision-Making

Treatment Indications

Treatment should be initiated for:

1. Patients with cirrhosis and any detectable HBV DNA regardless of ALT levels 2
2. Patients with HBV DNA >20,000 IU/mL and ALT >2× ULN 2
3. Patients with HBV DNA >2,000 IU/mL and ALT >ULN, or significant fibrosis 2
4. Patients with HIV/HBV co-infection regardless of disease status 1

First-Line Treatment Options

• Preferred agents due to high barrier to resistance:

  • Entecavir (0.5 mg daily) 3
  • Tenofovir disoproxil fumarate (300 mg daily) 4
  • Tenofovir alafenamide (25 mg daily) 2

• Avoid lamivudine, telbivudine, or emtricitabine as monotherapy due to high risk of resistance 2

Special Populations

• HIV/HBV co-infection: Use tenofovir-containing regimen as part of antiretroviral therapy 1, 2
• Decompensated cirrhosis: Use tenofovir or entecavir and consider liver transplantation referral 2
• Patients requiring immunosuppressive therapy: Start antiviral prophylaxis before immunosuppression and continue for at least 12 months after completion 2

Monitoring and Follow-up

During Treatment

• ALT and HBV DNA every 3-6 months
• HBeAg/anti-HBe status every 6-12 months
• Renal function every 6 months (especially with tenofovir) 2

HCC Surveillance

• Abdominal ultrasound every 6 months for high-risk patients:
  • All patients with cirrhosis
  • Asian men >40 years
  • Asian women >50 years
  • Family history of HCC
  • African Americans >20 years
  • Carriers >40 years with elevated ALT or HBV DNA >2000 IU/mL 2

Treatment Duration

• HBeAg-positive patients: Minimum 1 year, with continuation for 3-6 months after confirmed HBeAg seroconversion 2
• HBeAg-negative patients: Long-term or indefinite treatment typically required 2
• Cirrhotic patients: Indefinite treatment recommended 2

Common Pitfalls to Avoid

1. Failing to confirm chronicity - A single positive HBsAg test is insufficient; confirmation with a second test after 6 months is essential 1

2. Abrupt discontinuation of antiviral therapy - Can lead to severe hepatitis flares; treatment should never be stopped suddenly 2

3. Inadequate monitoring - Regular monitoring of viral load, liver function, and HCC surveillance is critical for early detection of complications or treatment failure 2

4. Using low-barrier-to-resistance antivirals - Lamivudine, telbivudine, or emtricitabine monotherapy should be avoided due to high resistance rates 1, 2

5. Missing coinfections - All HBsAg-positive patients should be screened for HIV, HCV, and HDV 1, 2