Detection of hepatitis C virus genome is the only method currently available for detecting viremia in infected individuals. We describe a substantial simplification of current methods for viral RNA reverse transcription and polymerase chain reaction amplification, which allows cDNA synthesis and nested amplification in a single tube; this is achieved through compartmentalization of the reagents for the two reactions with a wax barrier. This procedure retains a high sensitivity: analysis of serum samples from hemodialysis patients, a high-risk group for hepatitis C virus infection, confirmed the presence of the virus in 88% of antibody-positive patients and detected viremia in patients without serological or biochemical evidence of hepatitis C virus infection.