Use

For detection of mutations in the genotype 3 NS5A gene associated with resistance to NS5A inhibitors such as daclatasvir and velpatasvir, including the clinically relevant Y93H polymorphism. NS5A RAVs are associated with reduced sustained virologic response (SVR), particularly in genotype 3 patients treated with velpatasvir-containing regimens. For example, SVR rates were 88% in patients with any baseline NS5A RAVs, 84% in those with Y93H, compared to 97% in those without RAVs. Resistance results can guide the addition of ribavirin or selection of alternative regimens per AASLD‑IDSA guidelines. Quest employs RT‑PCR and DNA sequencing targeting codons 1–150 of NS5A to identify RAVs, especially Y93H. The assay requires an HCV RNA viral load of at least 1,000 IU/mL for reliable performance.