Acute hepatitis C refers to the first 6 months after an infection. Symptoms can begin within 2-26 weeks after infection. A detectable HCV RNA by polymerase chain reaction (PCR) in the setting of undetectable anti-HCV antibodies that subsequently become detectable within 12 weeks is generally considered definitive proof of acute HCV infection. Enzyme-linked immunosorbent assay (ELISA) tests detecting anti-HCV antibodies become positive as early as eight weeks after exposure, with most patients seroconverting between two and six months after exposure. If the HCV antibody is positive at this time point but the HCV RNA is negative, that is suggestive of a prior, cleared HCV infection, and this should be confirmed with repeat HCV RNA after 12 weeks. We typically recheck the HCV RNA at 12 weeks following the estimated date of infection (since most patients who spontaneously clear HCV will do so within this time frame) and initiate treatment if still detectable. Detectable HCV RNA at 12 weeks after exposure predicts chronicity of hepatitis C and indicates a requirement for treatment to prevent ongoing transmission in high-risk groups. Around 25% of patients (but potentially up to 35-40% by some estimates) will spontaneously clear their infections, while 75% will progress to chronic infection, of which 20-30% will develop cirrhosis.
References: Hepatitis C