What laboratory tests should be ordered to evaluate a patient with suspected or confirmed hepatitis B virus infection?

Laboratory Evaluation for Hepatitis B Virus Infection

Core Serologic Panel

Order HBsAg, total anti-HBc, and anti-HBs as the initial three-marker panel to determine infection status, immunity, and need for vaccination. 1, 2, 3

• HBsAg identifies current infection (acute or chronic) and is the first marker to appear, typically 30 days after exposure 3
• Total anti-HBc (IgG) confirms any past or present HBV exposure and persists for life after infection 1, 3
• Anti-HBs indicates either vaccine-induced immunity or recovery from natural infection 1, 3

Distinguishing Acute from Chronic Infection

If HBsAg is positive, immediately add IgM anti-HBc to differentiate acute from chronic infection. 1, 2, 4

• IgM anti-HBc positive = acute infection (detectable up to 6 months) 1, 3, 5
• IgM anti-HBc negative with HBsAg positive for >6 months = chronic infection 1, 2
• Repeat HBsAg testing at 6 months to confirm chronicity if initial presentation timing is unclear 1, 2

Essential Viral Replication Markers for Chronic Infection

All HBsAg-positive patients require HBeAg/anti-HBe status and quantitative HBV DNA to determine disease phase and treatment eligibility. 1, 2, 4

HBeAg and Anti-HBe Testing

• HBeAg positive indicates high viral replication and defines immune-active or immune-tolerant phases 1, 2
• HBeAg negative with anti-HBe positive requires HBV DNA quantification to distinguish inactive carriers (HBV DNA <2,000 IU/mL) from HBeAg-negative chronic hepatitis B (HBV DNA ≥2,000 IU/mL) 1, 2
• Recheck HBeAg/anti-HBe every 6-12 months in HBeAg-positive patients to detect seroconversion 2, 4

Quantitative HBV DNA

• HBV DNA ≥20,000 IU/mL in HBeAg-positive patients with elevated ALT defines treatment-eligible chronic hepatitis B 1, 2, 4
• HBV DNA ≥2,000 IU/mL in HBeAg-negative patients with elevated ALT indicates HBeAg-negative chronic hepatitis B requiring treatment consideration 1, 2
• HBV DNA <2,000 IU/mL with normal ALT in HBeAg-negative patients suggests inactive carrier state 1, 2
• Measure HBV DNA every 3-6 months even in presumed inactive carriers, as 15-35% develop viral reactivation over time 2

Comprehensive Liver Disease Assessment

Obtain a complete metabolic liver panel to assess synthetic function and degree of hepatocellular injury. 1, 4

• Complete blood count with platelets (cytopenias suggest portal hypertension) 1, 4
• AST/ALT (monitor every 3-6 months; elevation >2× ULN for 3-6 months with appropriate HBV DNA thresholds triggers treatment) 1, 2, 4
• Alkaline phosphatase, gamma-glutamyl transpeptidase 1
• Total bilirubin, albumin, prothrombin time/INR (assess synthetic function) 1, 4
• Creatinine (baseline renal function, especially if tenofovir therapy anticipated) 2

Mandatory Coinfection Screening

Test all HBsAg-positive patients for HIV, hepatitis C, and hepatitis D to identify coinfections that accelerate liver disease progression and alter treatment strategy. 1, 2, 4

• Anti-HCV antibody (hepatitis C coinfection significantly worsens prognosis) 1, 4
• Anti-HDV in persons who inject drugs or have other parenteral exposure risk 1, 4
• Anti-HIV in all patients (coinfection accelerates fibrosis and requires modified treatment approach) 1, 4

Hepatitis A Immunity Assessment and Vaccination

Measure IgG anti-HAV in all HBsAg-positive patients younger than 50 years; vaccinate all seronegative individuals with two doses 6-18 months apart. 1, 2, 4

• Acute hepatitis A superinfection in chronic HBV patients causes more severe hepatic injury, longer recovery, and increased risk of fulminant hepatic failure 1
• Anti-HAV seroprevalence has declined markedly in younger cohorts due to improved hygiene, making screening and vaccination essential 1, 6
• Underlying chronic liver disease is a major risk factor for fulminant hepatic failure and death from acute HAV infection 1

Hepatocellular Carcinoma Surveillance

Perform baseline abdominal ultrasound and serum α-fetoprotein in all HBsAg-positive patients aged ≥20 years at initial presentation. 1, 2, 4

• Continue ultrasound surveillance every 6 months for high-risk patients: all cirrhotic patients, Asian men >40 years, Asian women >50 years, Africans >20 years, and those with family history of HCC 2, 4
• AFP can be added to ultrasound but ultrasound alone has superior sensitivity and specificity 2

Fibrosis Assessment

Use non-invasive transient elastography as the preferred initial method for staging liver fibrosis. 2, 4

• Reserve liver biopsy for indeterminate cases, suspected additional liver pathology, or when non-invasive methods are inconclusive 1, 2
• Reassess fibrosis periodically using non-invasive methods to detect progression 2

Critical History Elements

Document family history of HBV infection, cirrhosis, and hepatocellular carcinoma; a positive family history warrants treatment consideration even without advanced fibrosis. 1, 4

• Quantify alcohol consumption and counsel complete abstinence, as alcohol accelerates progression to cirrhosis 1, 4
• Review all current and planned medications, especially immunosuppressive therapy, chemotherapy, or biologics that require antiviral prophylaxis 2, 4
• Identify all household members, sexual partners, and needle-sharing contacts for screening and vaccination 2, 4

Contact Screening and Vaccination

Screen all household members, sexual partners, and needle-sharing contacts with HBsAg, anti-HBc, and anti-HBs; vaccinate susceptible contacts immediately without awaiting serologic results. 2, 4

• Administer the first vaccine dose at the time of blood draw rather than waiting for results 2
• Counsel patients that HBV spreads via blood, sexual contact, and perinatal routes 2
• Advise against sharing toothbrushes, razors, or injection equipment 2, 4

Common Pitfalls to Avoid

Never rely on a single HBV DNA or ALT measurement to determine disease phase or treatment eligibility; levels fluctuate markedly, especially in HBeAg-negative disease. 2, 3

• Do not assume HBeAg-negative/anti-HBe-positive patients are inactive carriers without confirming HBV DNA <2,000 IU/mL and persistently normal ALT over serial measurements 2, 3
• Isolated anti-HBc positivity may represent occult HBV infection; test HBV DNA in immunocompromised patients or those from high-prevalence regions 1, 2, 3
• Patients with exacerbations of chronic infection can test positive for IgM anti-HBc, potentially leading to misdiagnosis as acute infection 3, 5
• HBsAg can be transiently positive for up to 18 days after hepatitis B vaccination; this is clinically insignificant 3

Ongoing Monitoring Schedule for Untreated Patients

Check ALT/AST every 3-6 months and quantitative HBV DNA every 3-6 months indefinitely, as patients can transition between disease phases. 1, 2, 4

• If ALT rises above upper limit of normal in previously normal patients, increase monitoring frequency to every 1-3 months and recheck HBV DNA 2
• Patients over age 40 with persistent ALT elevation warrant closer monitoring due to increased mortality risk from liver disease 2