External quality assessment programmes for detection of HCV RNA, HIV RNA and HBV DNA in plasma: improved proficiency of the participants observed over a 2-year period

Background and objectives: Two External Quality Assessment Programmes (EQAPs) were run in 2008 and 2009 to evaluate the proficiency of blood centres in detecting, by nucleic acid amplification techniques (NAT), the possible contamination of plasma with hepatitis C virus (HCV), human immunodeficiency virus (HIV) and hepatitis B virus (HBV).

Materials and methods: In the EQAP-2008, three customized panels were designed; each containing positive samples with a viral nominal concentration for the three viruses of about three times the 95% DL of the respective commercial NAT assay. In the EQAP-2009, the proficiency of the participants was evaluated with a single panel, independently on the NAT method used.

Results: While 84% (102/122) of the participants in the EQAP-2008 correctly identified the positive and negative samples of the panels, in the EQAP-2009 the percentage of proficient laboratories increased to 97% (118/122). Most importantly, in this 2-year experience, we observed a decrease in the number of pre-/postanalytical errors, from 14 in 2008 to two in 2009.

Conclusions: The design of these two EQAPs allowed participants to assess the performance of the NAT methods applied in their routine screening of blood donations, not only with respect to analytical errors but also to human errors that, despite the high level of automation reached by NAT methods, can still occur.