Infection with hepatitis C virus (HCV) is a matter of great concern because of its potentially grave consequences. Instead of relying on the conventional anti-HCV antibody test to detect HCV infection after needlestick incidents, we used the polymerase chain reaction (PCR) to achieve earlier detection, to manage a patient more effectively, and to exclude possible infection more quickly. Fourteen incidents were studied in which the source patients were positive for both the anti-HCV antibody and HCV RNA, and the exposed subjects were negative for anti-HCV antibody at the time of the incidents. In one of the exposed subjects, a nurse, the result of the PCR test for HCV RNA was positive at 2 wk after the needlestick incident; the nurse's viral load was very low (800 copies/ml) and she responded well to immediate medical treatment. She never developed acute hepatitis C; her serum anti-HCV antibody level and alanine aminotransferase (ALT) activity did not become elevated, and results of her PCR test for HCV RNA were negative following treatment. In the other 13 needlestick incidents, the results of PCR tests of the exposed subjects were negative for HCV RNA throughout the study and possible infections were quickly ruled out.