Discrepant diagnostic results using two genotyping methods in a chronic hepatitis C patient in serogroup 1

We present the case of a chronic hepatitis C (CHC) patient who was originally diagnosed with genotype 2a on serogroup 1 CHC genotype testing, but who was subsequently confirmed to have genotype 1b when using the hepatitis C virus (HCV) monitor genotype assay. The genotype 2a diagnosis was attributed to the fact that the type 2a-specific primer used in Okamoto et al.'s method (HCV genotype primer kit) has relatively high homology, which caused the amplification reaction to proceed, rendering a HCV RNA genotype test result of 2a. Genotype testing is important in determining whether a patient is indicated for concomitant dual oral therapy; however, the potential for different diagnoses such as described in this report highlights the importance of serogroup confirmation.