A nurse develops clinical symptoms consistent with hepatitis. She recalls sticking herself with a needle approximately 4 months ago after drawing blood from a patient. Serologic tests for HBsAg, antibodies to HBsAg, and hepatitis A virus (HAV) are all negative; however, she is positive for lgM core antibody. The nurse
High-Yield Explanation
In a small number of patients with acute hepatitis B infection, HBsAg can never be detected. In others, HBsAg becomes negative before the onset of the disease of before the end of the clinical illness. In such patients with acute hepatitis, hepatitis B virus infection may only be established by the presence of antihepatitis B core lgM (anti- HBc lgM), a rising titer of anti-HBc, or the subsequent appearance of anti-HBsAg.