In acute hepatitis B infection, which serologic pattern is typical?

• A. HBsAg negative, HBsAb positive, HbcAb IgM positive
• B. HBsAg positive, HBsAb negative, HbcAb IgM positive
• C. HBsAg positive, HBsAb positive, HbcAb IgM negative
• D. HBsAg negative, HBsAb negative, HbcAb IgM positive

Answer: (B)

In acute hepatitis B, the virus is actively replicating, so the surface antigen (HBsAg) is detectable in the blood. The body has not yet produced protective surface antibodies, so anti-HBs is negative. The first antibody to HBV that rises during the acute phase is IgM anti-HBc, which indicates a recent infection. Putting those together gives the typical serologic pattern: HBsAg positive, anti-HBs negative, and IgM anti-HBc positive. This contrasts with other stages: once recovery occurs, anti-HBs becomes positive; during the window period after HBsAg has disappeared but before anti-HBs appears, anti-HBc IgM is still positive but HBsAg is negative and anti-HBs remains negative.