External quality assurance program in anti-HCV serological detection: an Italian experience

Abstract Here, we reported the results collected in the 2002 cycle of the “Serocheck” External Quality Assessment (EQA) scheme for the detection of antibodies against the hepatitis C virus (anti-HCV). This program, conducted by the Institute of Clinical Physiology, CNR, Pisa in co-operation with Polymed (Firenze, Italy), involved about 80 among microbiology, transfusional and general Italian laboratories. Methods. – The reference panel sent to the laboratories consisted of 12 samples. Three series of samples, from a pool of donors, were negative for anti-HCV. The positive panel, obtained by different dilutions of positive pools with the negative one, was constituted by two samples with concentration higher than 10× cut-off (A), two samples between 4× cut-off and 10× cut-off (B), four samples between 2× cut-off and 4× cut-off (C) and one sample borderline (1.22× cut-off) (D). Results. – On the whole number of serum samples, the percentage of correct results was 95% (1.2% doubtful and 3.8% incorrect). The positive samples were identified in the 93.3% (1.4% doubtful, 5.3% incorrect), while the negative ones in the 99.5% of the cases (0.5% incorrect). The A series of samples was detected in 97.5% (2.5% incorrect), the B series in 96% (4% incorrect) and the C series in 96.7% (3.3% incorrect) and the D series was detected in 64.5% (13.5% doubtful and 22% incorrect) of the cases. Conclusion. – Results of the present study indicate that the running quality control study is needed that allows the comparison of results from different laboratories less difficult and a reliable evaluation of their performance. In addition, the percentage of incorrect result for D series is disquieting and makes crucial the importance of control quality schemes.