Evaluation of the Abbott RealTime HCV genotype II plus RUO (PLUS) assay with reference to core and NS5B sequencing.
HCV genotyping remains a critical tool for guiding initiation of therapy and selecting the most appropriate treatment regimen. Current commercial genotyping assays may have difficulty identifying 1a, 1b and genotype 6.



To evaluate the concordance for identifying 1a, 1b, and genotype 6 between two methods: the PLUS assay and core/NS5B sequencing.



This study included 236 plasma and serum samples previously genotyped by core/NS5B sequencing. Of these, 25 samples were also previously tested by the Abbott RealTime HCV GT II Research Use Only (RUO) assay and yielded ambiguous results. The remaining 211 samples were routine genotype 1 (n=169) and genotype 6 (n=42). Genotypes obtained from sequence data were determined using a laboratory-developed HCV sequence analysis tool and the NCBI non-redundant database.



Agreement between the PLUS assay and core/NS5B sequencing for genotype 1 samples was 95.8% (162/169), with 96% (127/132) and 95% (35/37) agreement for 1a and 1b samples respectively. PLUS results agreed with core/NS5B sequencing for 83% (35/42) of unselected genotype 6 samples, with the remaining seven "not detected" by the PLUS assay. Among the 25 samples with ambiguous GT II results, 15 were concordant by PLUS and core/NS5B sequencing, nine were not detected by PLUS, and one sample had an internal control failure.



The PLUS assay is an automated method that identifies 1a, 1b and genotype 6 with good agreement with gold-standard core/NS5B sequencing and can aid in the resolution of certain genotype samples with ambiguous GT II results.
ARUP Institute for Clinical and Experimental Pathology, ARUP Laboratories, 500 Chipeta Way, Salt Lake City, UT 84108, USA. Electronic address: melanie.mallory@aruplab.com.
Melanie A
MA
Mallory
Abbott Molecular Inc, 1350 E. Touhy Avenue, Des Plaines, IL, 60018, USA. Electronic address: danijela.lucic@abbott.com.
Danijela
D
Lucic
Department of Neuroscience, Mayo Clinic, 4500 Pablo Road, Jacksonville, FL, 32224, USA. Electronic address: ebbert.mark@mayo.edu.
Mark T W
MT
Ebbert
Abbott Molecular Inc, 1350 E. Touhy Avenue, Des Plaines, IL, 60018, USA. Electronic address: gavin.cloherty@abbott.com.
Gavin A
GA
Cloherty
Abbott Molecular Inc, 1350 E. Touhy Avenue, Des Plaines, IL, 60018, USA. Electronic address: dan.toolsie@abbott.com.
Dan
D
Toolsie
ARUP Institute for Clinical and Experimental Pathology, ARUP Laboratories, 500 Chipeta Way, Salt Lake City, UT 84108, USA; Department of Pathology, University of Utah, 15 North Medical Drive East, Salt Lake City, UT 84112, USA. Electronic address: hillyadr@aruplab.com.
David R
DR
Hillyard
D057205:Automation, Laboratory / Q000379:methods; D005838:Genotype; D060005:Genotyping Techniques / Q000379:methods*; D016174:Hepacivirus / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D006526:Hepatitis C / Q000821:virology*; D014758:Viral Core Proteins / Q000235:genetics*; D017361:Viral Nonstructural Proteins / Q000235:genetics*; D012324:RNA-Dependent RNA Polymerase
D014758:Viral Core Proteins; D017361:Viral Nonstructural Proteins; C069130:nucleocapsid protein, Hepatitis C virus; C087036:NS-5 protein, hepatitis C virus; D012324:RNA-Dependent RNA Polymerase
DNA sequencing; Genotyping; Hepatitis C virus; Real-time PCR