Testing of the serum samples from both patients gave an indeterminate result with the Abbott assay. By contrast, the Versant assay gave an indeterminate result for one patient and identified an HCV-2b subtype in the other patient. Phylogenetic analysis of the NS5B region confirmed the presence of HCV-2b in this latter patient and disclosed the presence of HCV-3h in the other patient. Sequencing of the 5¡ä-UTR revealed the presence of nucleotide changes at positions ?166 and ?119 of HCV-2b, and at positions ?138, ?108 and ?99 of HCV-3h.
Nucleotide mutations located in the 5¡ä-untraslated region of hepatitis C virus may impair the ability of commercial assays to assign an HCV genotype.