Accurate genotyping is important to improve the treatment of hepatitis C virus (HCV) infection. We herein report a 44-year-old Japanese man with hemophilia A and coinfection of HCV and human immunodeficiency virus (HIV) who was diagnosed with HCV genotype 4 by direct sequencing. Two genotyping tests based on the nested polymerase chain reaction method that we used misdiagnosed his genotype as 2b and 1b. Although several HCV genotyping tests are available in Japan, it is important to recognize that some cannot detect genotype 4. Care should be taken when genotyping HCV patients who have received non-heated coagulation factor preparations or were infected abroad.
Keywords: direct-acting antiviral agent; genotype 4; genotyping; hepatitis C virus.