Hepatitis B Serology — Pattern Interpretation

Three antigens (HBsAg, HBcAg, HBeAg) + their antibodies (anti-HBs, anti-HBc, anti-HBe). PATTERNS: • Acute infection: HBsAg+, anti-HBc IgM+, HBeAg+, anti-HBs− • Chronic infection: HBsAg+ (>6 mo), anti-HBc IgG+, HBeAg ± • Window period: HBsAg−, anti-HBs−, anti-HBc IgM+ (only IgM detectable) • Resolved past infection: HBsAg−, anti-HBs+, anti-HBc IgG+ • Vaccinated (no past infection): HBsAg−, anti-HBs+, anti-HBc− KEY: • HBsAg = active infection (acute or chronic) • Anti-HBs = immunity (vaccine OR resolved) • Anti-HBc = ever exposed (separates vaccine from natural) • HBeAg = high replication / infectivity Treatment chronic HBV: • Tenofovir, Entecavir (first-line) • Pegylated interferon (selected cases)