ABSTRACT
Objective To analyze hepatitis B virus(HBV) infection stage in single nucleic acid test(NAT)reactive blood donors.Methods Blood donor samples were screened routinely for HBV DNA by using transcription-mediated amplification(TMA) NAT and quantitative polymerase chain reaction(PCR).Then serum markers of HBV were also detected.The HBV infection stage was analyzed.Results Among the 225 single NAT reactive samples,78(34.67%) were identified to be reactive for HBV DNA by TMA NAT discrimination test and/or PCR test,of which 63(82.89%) were occult HBV infection(OBI),13(17.11%) were probably window period infection(pWP),and 2 cases could not be classified for infection stage.Among the OBI samples,49 samples(77.78%) were with HBV DNA concentration less than 20 IU/mL,whereas,there were only 4 samples(30.77%) in pWP samples.The 225 samples were classified into three groups according to the S/CO of NAT, including 1-<6 group,6-<10 group and 10-17 group, the confirmed HBV DNA positive rates of which were 13.11%,13.64% and 47.18%,and the positive rate of 10-17 group was higher than 1-<6 group and 6-<10 group(P<0.05).In all 63 OBI samples,there were 8(12.70%),3(4.76%) and 52(82.54%) samples were classified into S/CO 1-<6,6-<10 and 10-17,respectively.All of the 13 pWP samples were with NAT S/CO of 10-17.Conclusion Part of single NAT reactive blood donors could be with HBV infection,of which OBI might be popular than pWP, with very low concentration of HBV DNA.Deferral of single NAT reactive blood donors could reduce transfusion-transmitted HBV infection.
ABSTRACT
ObjectiveTo investigate the effect of individual donation-nucleic acid amplification test (ID-NAT) and minipool of 16 donations-NAT (P16-NAT) on the results of NAT of blood donors.Methods From February 2009 to June 2009,samples randomly collected from voluntary blood donors in Beijing were tested individually or in pooling of 16 donations by the PROCLEIX ULTRIO assay.For ID-NAT reactive samples with HBsAg,anti-HCV,or anti-HIV serologically unqualified,ID-NAT repeat reactive samples with serologically qualified,and P16-NAT reactive and followed resolution ID-NAT reactive samples,were performed for further discriminatory assays for HIV-1,samples and followed resolution ID-NAT reactive samples,were performed for further discriminatory assays for HBV,HCV and HIV-1discriminatory reagents.Samples which were HBV NAT + alone with serologically qualified were further quantified and confirmed of HBV DNA by Roche HBV quantitative PCR,analyzed by HBV serology and were diluted to simulate if they could be detected in P16-NAT.Results ( 1 ) Among 7613 samples tested by ID-NAT,26 were NAT positive,i.e.the ID-NAT positive rate was 0.34％ ( 26/7613 ). ( 2 ) Among 1004 P16 samples from 16 064 blood donations,27 were NAT positive,i.e.the P16-NAT positive rate was 0.17％ (27/16 064).(3)In serological qualified donations,ID-NAT yield rate (1 in 826,9/7438 ) was much higher than P16-NAT ( 1 in 7875,2/15 750) (x2 =11.880,P ＜ 0.05 ).All these 9 ID-NAT positive and 2 P16-NAT positive donations were discriminated as HBV NAT positive.There were no HCV NAT yield or HIV NAT yield samples. (4) Dilution assay showed only 2 of the 9 (22.22％ ) ID-NAT HBV yields were detected by P16-NAT.(5)Eight ID-NAT and 2 P16-NAT positive samples were quantified for HBV DNA and confirmed as HBV NAT yield,although the virus loads were very low:2 samples had HBV viral loads of 15 IU/ml and 472 IU/ml,6 samples ＜ 12 IU/ml,and 2 could not be detected in the original samples while had ＜ 12 IU/ml and 14.3 IU/ml in the 10 times concentrated samples.(6)Among 11 HBV NAT yield cases,3 (27.3％ ) were possible HBV window-period donors with all HBV seromarkers negative,the other 8 (72.7％ ) had occult HBV infections with anti-HBc or anti-HBe positive,however anti-HBc IgM negative.(7) The rate of initial P16-NAT reactive pools needed to be further tested by ID-NAT was 2.49％(25/1004).Initial P16-NAT reactive pools which caused by serologically qualified donations was 0.20％(2/1004).ConclusionsHBV NAT yield cases are detected at a higher frequency with ID-NAT than P16-NAT.In order to avoid samples with low viral loads would be undetected,NAT assay with high sensitivity should be selected and tested in minimized minipool donations or even with individual donation.