Nucleic acid testing (NAT) for HCV RNA in Italian transfusion centres: An external quality assessment

BackgroundWe conducted an external quality assessment of the results obtained in Italian transfusion centre laboratories employing nucleic acid testing (NAT) for detection of HCV RNA in donated blood.Study designOf 110 transfusions centres in Italy, 101 voluntarily participated. Each laboratory received seven separate shipments of samples for HCV RNA testing by NAT. Each shipment contained 8 plasma samples for a total of 23 negative and 33 positive samples with viral loads ranging from 25 to 1000 IU/mL.ResultsOf the 2080 HCV RNA-negative samples, 14 (0.7%) were reported as positive. The highest percent of false-negative results (6.9%) was found on samples from the first shipment with viral loads from 75 to 100 IU/mL. In subsequent shipments, the highest false-negative percentage ranged from 0.6% for samples with viral loads of 170–1000 IU/mL to 3.4% for samples with viral loads of 35–50 IU/mL. A false-negative rate of 4.9% occurred in samples in the sixth shipment with the lowest viral load (25 IU/mL). Five (4.9%) centres were identified as having laboratories with low-performance. There were no significant differences among genotypes 1b, 2c and 3a with respect to percent of false-negative results reported.ConclusionsOverall, the accuracy of NAT observed in this study of Italian transfusion centre laboratories was excellent for all HCV genotypes tested, even for samples with low HCV RNA titres.