HCV and HBV Infections Interdicted by Individual Donation (ID)-NAT Testing In Lithuania

Abstract

Background: In Lithuania the transition to a system of voluntary nonremunerated blood donors has not yet been completed. To minimize the risk of virus transmission National Blood Center implemented ID-NAT screening of all blood components in September 2005, using the semiautomated Ultrio system, which was replaced by the fully automated Tigris Procleix platform in June 2006. Aim: To determine the HBV, HCV and HIV NAT yield rates. Methods: Blood donations are tested for HBsAg, anti-HCV and anti-HIV1/ 2 by AxSYM (Abbott), and to reduce NAT contamination risk only the seronegative donations are tested individually for HBV-DNA, HCV-RNA and HIV-RNA by the HBV/HCV/HIV-1 Procleix Ultrio test. NAT reactive units are repeated in duplicate Ultrio tests as well as by discriminatory probe (dHXV) assays. The dHCV reactive potential NAT yield donations were tested for HCV-RNA load (Bayer Versant bDNA, later Roche Taqman assay) and HCV genotype (InnoLipa). Ultrio repeat and/or HBV reactives were confirmed by HBV-PCR (1 mL Roche Ampliscreen, later Taqman assay) and by anti-HBc AxSYM. Unfortunately it was not feasible to recall donors for confirmation of seroconversion in follow up samples. Results: A total of 116 798 seronegative donations had been screened by Ultrio, 401 (0.34%) were initial Ultrio reactive and 65 (0.06%) were repeat and/or dHXV reactive. 34 (0.03%) were dHCV reactive, 15 (0.01%) dHBV reactive and 16 (0.01%) Ultrio repeat reactive, but dHXV negative. So, the Ultrio non repeat (false) reactive rate was 0.29 %. Of 34 dHCV reactive potential NAT yield cases 29 have been tested for viral load of which 26 were reactive with the following distribution: 100 % > 103 cps/mL, 96 % > 104, 73 % > 105, 46 % > 106 and 23 % > 107 cps/mL. Three dHCV reactive donors were not confirmed in the Taqman PCR assay or could have a viral load below the detection limit (<60 cps/mL). The HCV genotype could be determined in 24 window phase donations, of which seven (29%) were typed 1.