Quantification of genotype 4 hepatitis C virus RNA by the COBAS AmpliPrep/COBAS TaqMan hepatitis C virus test

HCV RNA measurement in samples with diverse genotypes using versions 1 and 2 of the Roche COBAS® AmpliPrep/COBAS® TaqMan® HCV test

“…However, we examined 15,817 5 UTR sequences from our clinical sample database, and only one (0.0063%) had both nt145 and nt165 variants [8]. Our results comparing V2 to V1 and our analysis of archived sequences agrees with those reported by Germer et al [10], in which 100 genotype 4 samples were compared in V1 and bDNA; no nt145 variants and six (6%) nt165 variants were observed. Germer et al [10] also reported finding only three genotype 4 sequences with both nt145 and nt165 variants in their search of Genbank sequences.…”

“…These assays have been designed for equivalent detection of all six genotypes of HCV. However, reports of underquantification and complete failure to detect certain HCV isolates, particularly genotype 4, have been published for version 1 of the COBAS ® AmpliPrep/COBAS ® TaqMan ® HCV Test (V1), mostly originating from laboratories outside the United States [6][7][8][9][10][11]. These failures have been associated with sequence variants at nt145 and nt165 in the 5 UTR [8].…”

Development of a Second Version of the Cobas AmpliPrep/Cobas TaqMan Hepatitis C Virus Quantitative Test with Improved Genotype Inclusivity

“…Among these, several report underestimation of HCV RNA levels in up to 30% of GT4 specimens compared to competitor assays (2,16,17,20,22). Recently, the hypothesis was established that these findings were linked to the occurrence of GT4 specimens harboring amino acid substitutions at positions 145 (G to A) and 165 (A to T) in the 5ЈUTR of the HCV genome (1,3,8,10).…”

Second-Generation Cobas AmpliPrep/Cobas TaqMan HCV Quantitative Test for Viral Load Monitoring: a Novel Dual-Probe Assay Design

“…The CAP/CTM HCV test, v2.0, was developed as a secondgeneration assay by using a novel dual-probe approach and an additional reverse primer to improve genotype 4 inclusivity and performance with known samples found to be difficult to quantify (18)(19)(20). In addition, an improved sample preparation method included changes in the elution and lysis buffers, as well as a higher temperature for the reverse transcriptase step and shorter overall PCR cycles.…”