Hepatitis C Viral RNA, Genotype

Determination of hepatitis C genotype may be required to select the most appropriate direct-acting agent(s) (DAA) for the treatment of hepatitis C. For guidance, refer to the package inserts of the relevant DAAs or to the AASLD and IDSA Recommendations for Testing, Managing and Treating Hepatitis C .¹ A concurrent HCV viral load of 2,000 IU/mL is usually required for this test.

The HCV RNA genotype test can detect all 6 major HCV genotypes (1–6) and HCV subtypes 1a and 1b.

The HCV RNA genotype test is performed by nucleic acid extraction, reverse transcription, polymerase chain reaction (PCR) amplification, and Sanger DNA sequencing.

For most HCV genotypes, a viral load of at least 2,000 IU/mL will enable successful detection of the HCV genotype. In some cases, the genotype will not be detected due to low viral load, mutations in the viral genome at PCR priming sites, or other undetermined factors.

The HCV RNA genotype test is designed to detect all 6 major HCV genotypes. The NS3, NS5a, and NS5b genotype tests, on the other hand, detect mutations associated with drug resistance.

Drug resistance genotype tests are not intended for determining HCV genotypes, as they are limited to specific HCV genotypes: genotype 1 for NS3 and NS5b, and genotypes 1 and 3 for NS5a.The Hepatitis C Viral RNA, Genotype test should be performed before ordering a drug resistance test.

More guidance can be found in the AASLD and IDSA recommendations for testing, managing, and treating HCV.¹