What are the diagnostic tests and management options for hepatitis B?

Diagnostic Tests and Management of Hepatitis B

Diagnosis of hepatitis B requires specific serological and virological markers, with management decisions based on disease phase, viral replication status, and liver damage assessment. 1

Diagnostic Tests for Hepatitis B

Serological Testing

• Initial screening tests:

  • HBsAg (hepatitis B surface antigen): Positive indicates current infection
  • Anti-HBs (antibody to HBsAg): Indicates immunity from vaccination or resolved infection
  • Anti-HBc (antibody to hepatitis B core antigen): Indicates previous or ongoing infection 1

• Additional serological markers:

  • HBeAg (hepatitis B e antigen): Indicates high viral replication and infectivity
  • Anti-HBe (antibody to HBeAg): Usually indicates lower viral replication
  • IgM anti-HBc: Indicates acute infection (positive during first 6 months) 1

Virological Testing

• HBV DNA quantification: Essential for:
  • Assessing viral replication level
  • Determining disease phase
  • Guiding treatment decisions
  • Monitoring response to antiviral therapy 1

Liver Disease Assessment

• Biochemical tests:

  • ALT/AST: Assess liver inflammation
  • Alkaline phosphatase, GGT, bilirubin: Evaluate liver function
  • Albumin, prothrombin time: Assess synthetic function 1

• Fibrosis assessment:

  • Liver biopsy (optional): Evaluates inflammation and fibrosis
  • Non-invasive methods: Transient elastography, serum fibrosis markers 1

• Imaging:

  • Ultrasound: Screens for HCC and assesses for cirrhosis 1

Diagnostic Interpretation

Acute Hepatitis B

• Positive HBsAg + positive IgM anti-HBc
• High HBV DNA levels
• Elevated ALT/AST 1

Chronic Hepatitis B (CHB)

• Definition: HBsAg positivity for >6 months 1
• HBeAg-positive CHB:
  • HBV DNA ≥20,000 IU/mL
  • Elevated ALT/AST 1
• HBeAg-negative CHB:
  • HBV DNA ≥2,000 IU/mL
  • Elevated ALT/AST 1

Inactive HBV Carrier State

• HBsAg positive >6 months
• HBeAg negative, anti-HBe positive
• HBV DNA <2,000 IU/mL
• Persistently normal ALT/AST 1

Resolved HBV Infection

• HBsAg negative
• Anti-HBs positive
• Anti-HBc positive 1

Occult HBV Infection

• HBsAg negative
• Detectable HBV DNA
• Usually anti-HBc positive 1

Management of Hepatitis B

Initial Evaluation

1. Complete history and physical examination:

   • Focus on alcohol consumption, drug use
   • Family history of liver disease and HCC 1

2. Laboratory assessment:

   • Complete blood count
   • Liver function tests
   • Coagulation profile
   • Renal function tests 1

3. Coinfection screening:

   • Anti-HCV, anti-HDV, anti-HIV 1

4. Immunity status:

   • IgG anti-HAV (for hepatitis A vaccination planning) 1

Treatment Indications

Treatment should be considered for:

• Patients with chronic HBV infection with:
  • HBV DNA ≥20,000 IU/mL (HBeAg-positive)
  • HBV DNA ≥2,000 IU/mL (HBeAg-negative)
  • Persistently elevated ALT/AST
  • Evidence of moderate-to-severe liver inflammation or fibrosis 1

Antiviral Therapy Options

• First-line agents:

  • Entecavir: 0.5 mg once daily (nucleoside analog) 2
  • Tenofovir: 300 mg once daily (nucleotide analog) 3

• Special considerations:

  • Renal impairment: Dose adjustment required for both medications
  • Decompensated cirrhosis: Careful monitoring needed
  • HIV coinfection: Use as part of appropriate antiretroviral regimen 2, 3

Monitoring During Treatment

• ALT/AST every 3-6 months
• HBV DNA levels every 3-6 months
• HBeAg and anti-HBe every 6-12 months in HBeAg-positive patients
• HBsAg quantification may help predict response
• Monitor for drug side effects (renal function for tenofovir, lactic acidosis for both) 1, 2, 3

Preventive Measures

• Vaccination:

  • HBV vaccination for all susceptible individuals
  • Hepatitis A vaccination for those without immunity 1, 4

• Lifestyle modifications:

  • Abstinence from alcohol and smoking
  • Avoid hepatotoxic medications 1

Long-term Monitoring

• HCC surveillance:

  • Ultrasound every 6 months for patients with cirrhosis or high risk factors
  • Consider alpha-fetoprotein testing 1

• Cirrhosis monitoring:

  • Endoscopic screening for varices if cirrhosis present
  • Regular assessment of liver function 1, 4

Common Pitfalls to Avoid

1. Misinterpreting serological patterns:

   • Isolated anti-HBc may represent occult HBV or resolved infection with waned anti-HBs
   • Window period during acute infection may show negative HBsAg but positive IgM anti-HBc 1

2. Inadequate monitoring:

   • Failure to monitor for HCC in high-risk patients
   • Insufficient follow-up of inactive carriers who may reactivate 1

3. Overlooking coinfections:

   • Not screening for HDV, HCV, or HIV in high-risk patients 1

4. Medication errors:

   • Using multiple tenofovir-containing products simultaneously
   • Not adjusting doses for renal impairment 3

5. Vaccination timing:

   • Delaying hepatitis A vaccination in chronic HBV patients
   • Not checking post-vaccination immunity in high-risk individuals 4