Hepatitis C Virus Genotypes in Clinical Specimens Tested at a National Reference Testing Laboratory in the United States

Hepatitis C virus (HCV) genotype (GT) distribution and frequency were studied among 22,407 unique specimens tested at a national reference testing laboratory. Subjects with HCV GT 3 were younger (P < 0.0001) than those with GT 1, 2, or 4, and the regional frequencies of HCV GT 2 and 3 ranged from 19.9% to 29.2%.