Utility of the Abbott RealTime HCV Genotype Plus RUO assay used in combination with the Abbott RealTime HCV Genotype II assay.

Background: Hepatitis virus C (HCV) genotype (GT) determination and subtype (ST) differentiation (1a versus 1b) remain important for the selection of appropriate direct-acting antiviral (DAA) therapy.

Objectives: This study is a retrospective comparison of HCV GT and ST result distribution when using the Abbott RealTime HCV Genotype II assay (HCVGT II) alone and in combination with the Abbott RealTime HCV Genotype Plus RUO assay (HCVGT Plus) for routine testing of clinical serum specimens at a reference laboratory.

Study Design: HCVGT II results of specimens tested from June 2014 through January 2016 (period 1) were compared with combined results from HCVGT II and HCVGT Plus (HCVGT II/Plus) performed from January 2016 through January 2017 (period 2).

Results: A total of 44,127 and 25,361 specimens were tested during periods 1 and 2, respectively. Use of HCVGT II/Plus significantly reduced the frequency of GT 1 results without ST (0.4%) when compared to preliminary HCVGT II results during period 2 (5.3%; p < 0.01) and final HCVGT II results in period 1 (5.5%; p < 0.01). HCVGT II/Plus also resulted in GT 6 reactivity in 38 specimens with results of "HCV detected" (n = 17) or GT 1 (n = 21) following initial HCVGT II testing during period 2.

Conclusions: When compared to the use of HCVGT II alone, HCVGT II/Plus significantly reduced the frequency of GT 1 without ST results observed in a large reference laboratory, while also enabling the identification of HCV GT 6.