External quality assessment for the molecular detection of Hepatitis C virus

Background, objectives and study designExternal quality assessment (EQA) panels were distributed internationally by UK NEQAS for Microbiology to 159 participants for the detection, quantification and genotyping of Hepatitis C virus (HCV) in freeze-dried plasma from 2000 to 2004. The results were analysed to determine the level of standardisation of qualitative detection, quantitative detection and genotyping.ResultsThe accurate detection of HCV in the panels varied from 86.9% to 100%. Four genotypes were distributed with the panels and there was no significant difference in the detection of different genotypes of HCV by participants. Further analysis indicated most variation occurred in quantification of HCV at lower concentrations and from 0% to 14.8% reported quantitative values outside 0.5 log10 of the median value. In addition, three negative specimens were distributed and false positives were found to be rare (0.9–2.2%) with all methods included in the study.ConclusionThe laboratory detection of HCV in plasma EQA specimens was varied, with decreasing parity of quantification at lower concentrations of HCV. False positives and negatives were rare, irrespective of the genotype under test.