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

Reliable resolution of ambiguous hepatitis C virus genotype 1 results with the Abbott HCV Genotype Plus RUO assay

“…Thus, we can estimate that the use of the GT Plus assay as a reflex test after the GT II assay would have decreased the overall ratio of HCV-1 samples in need of subtyping by the reference method from 5.7% down to 1.1%, which translates into a successful resolution of 98.9% of all HCV-1 samples when the two Abbott genotyping assays are combined. This corresponds well to the recently reported significant reduction of genotype 1 cases without subtype assignment down to 0.4% 33 and to the increase of the successful genotyping rate to >99% 11 .…”

“…21 ). An inability of the GT II assay to identify the genotype 1 subtype may be due to (i) the presence of genetic variability in the NS5B region in which the probes specific for subtype 1a or 1b detection anneal (majority in the present study), (ii) the presence of rare HCV-1 subtypes (four cases observed), or (iii) the presence of certain genotype 6 subtypes in which the 5′NC region targeted by the genotype 1-specific probe is identical to some 1b subtypes 11,13,33 (none observed in our study).…”

“…However, commercial genotyping assays may result in a low percentage of HCV-1 results with no subtype assigned 11–14,18–21 . The GT II assay, which targets the NS5B region for identifying subtypes 1a and 1b, may fail to resolve the subtype in about 5–12% of HCV-1 specimens 11,13,14,33 . However, a recent GT II software update has reduced the number of genotype samples without subtype assignment (4% in Herman et al .…”

“…We evaluated the performance and accuracy of the novel GT Plus assay in resolving HCV-1 specimens not subtyped by the GT II assay (Group 1) in comparison with the reference method or with LiPA. While three other evaluations of the GT Plus assay have previously been published 11,33,34 , the present study investigated HCV-1 specimens including the largest collection of very challenging clinical specimens with ambiguous HCV-1 results by GT II from three different geographical regions that was ever tested with the GT Plus assay and subsequently evaluated by a reference method for confirmation. Additionally, it was the first study in generating full core region sequences that shed some light into the reasons why this assay may not assign an HCV-1 subtype in rare cases.…”

Indeterminate genotypes of hepatitis C virus by the Abbott RealTime HCV Genotype II assay in Morocco. About eight cases resolved by a sequencing method

“…Hence, they developed the Abbott RealTi m e HCV Genotype Plus RUO assay. Recent studies assessed this new add‐on to the HCV genotyping kit, which resolves several indeterminate genotypes 1a, 1b, and 6 …”