Table 2.

Testing for Hepatitis C Virus Infection Following Exposure

Timing After Exposure	Laboratory Testing			Comment
	HCV EIA	HCV RNA	ALT
Source patient Immediate	Yes	If HCV EIA positive: Yes If HCV EIA negative: Recommend only if source is at risk for false-negative test	No	Although HCV RNA testing is not routinely recommended, it may be useful in immunocompromised source patients who may have false-negative serology.
Healthcare worker (if source patient has evidence of HCV infection)
Immediate	Yes	If HCV EIA positive: Yes	Yes	Healthcare worker does not require follow-up if source patient is HCV negative; however, baseline testing of HCW is prudent.
4–6 wk	Yes	Yes	Consider	If earlier diagnosis of HCV infection is desired, testing for HCV RNA may be performed to help guide treatment decision making. Due to the intermittent nature of HCV viremia in acute HCV infection, RNA testing should not be the sole screening test.
4–6 mo	Yes	Yes	Yes	HCV antibody testing 4–6 mo postexposure is considered the optimal means of detecting infection, although seronegative infections have been reported.

Abbreviations: ALT, alanine aminotransferase; EIA, enzyme immunoassay; HCV, hepatitis C virus; HCW, healthcare worker; RNA, ribonucleic acid.