Best Laboratory Test to Screen for HBV Infection
Hepatitis B surface antigen (HBsAg) is the best and recommended laboratory test to screen for hepatitis B virus infection. 1
Primary Screening Test
HBsAg testing using enzyme immunoassay (EIA) or radioimmunoassay (RIA) is the standard screening method, with sensitivity and specificity both exceeding 98% and detection limits below 0.5 ng/ml. 1
Modern chemiluminescent microparticle immunoassay (CMIA) and electrochemiluminescent immunoassay (ECLIA) platforms offer superior performance with detection limits as low as 0.05-0.08 IU/ml, compared to traditional ELISA (0.15 IU/ml) or rapid tests (15.0 IU/ml). 2
A positive HBsAg result indicates active HBV infection and infectiousness, whether acute or chronic. 3
Confirmatory Testing Algorithm
All reactive HBsAg screening tests require confirmatory testing with a neutralizing assay to establish true infection and exclude false positives. 3
If the initial HBsAg test is reactive, the sample should be retested in duplicate using the same test kit and manufacturer. 1
Repeatedly reactive results (one or both duplicate tests positive) should undergo neutralization testing according to manufacturer instructions before confirming infection status. 1
Additional Initial Evaluation After Positive HBsAg
Once HBsAg is confirmed positive, the following tests should be ordered to characterize the infection:
IgM anti-HBc (IgM antibody to hepatitis B core antigen) differentiates acute from chronic infection—positive IgM indicates acute hepatitis B. 3
Total anti-HBc should be positive in all chronic infections; its absence in an HBsAg-positive patient suggests very early acute infection or false-positive HBsAg. 3
HBeAg and anti-HBe assess viral replication status, with HBeAg-positive generally indicating high viral replication. 1, 3
Quantitative HBV DNA level is essential for determining disease activity and treatment eligibility, with levels >2,000 IU/ml typically indicating active viral replication. 1, 3
Anti-HBs (antibody to HBsAg) should be negative in chronic infection; if positive alongside HBsAg, this suggests either resolving acute infection or laboratory error. 3
Special Screening Populations
Universal screening is recommended for:
All pregnant women at the first prenatal visit, regardless of previous vaccination or prior negative tests, to prevent perinatal transmission. 1
Persons born in geographic regions with HBV prevalence ≥2% (including Asia, Africa, Pacific Islands), regardless of vaccination history in their country of origin. 1
U.S.-born persons not vaccinated as infants whose parents were born in regions with HBV endemicity >8%. 1
Men who have sex with men (MSM) and current or past injection drug users, who have higher HBV prevalence than the general population. 1
Persons receiving cytotoxic or immunosuppressive therapy (chemotherapy, organ transplant immunosuppression, biologics for rheumatologic/gastroenterologic disorders) to prevent reactivation. 1
Persons with unexplained persistently elevated ALT or AST levels. 1
Common Pitfalls to Avoid
Do not rely on rapid immunochromatographic assays (GICA) for definitive diagnosis—these have a false-negative rate of 12.3% compared to CMIA and are only suitable for preliminary screening. 2
Do not assume vaccination history eliminates the need for screening in high-risk populations, as many were infected before vaccine implementation or during early childhood before vaccination. 1
Do not use a single HBV DNA threshold (such as 20,000 IU/ml) to exclude chronic hepatitis B, as 30% of patients with HBeAg-negative chronic hepatitis B may be missed; serial monitoring is more important than any single cutoff value. 1
Do not screen for HBsAg alone in blood donors—all blood donations must also be tested for anti-HBc, as rare low-level HBsAg carriers may test falsely negative but remain infectious. 1