Applied Research On Nucleic Acid Amplification Technology In Blood Screening

Background:The existence of transfusion-transmitted infections (TTIs) is one of the major medical problems in transfusion therapy. In addition to traditionally monitored Hepatitis B virus, Hepatitis C virus, Human immunodeficiency virus and Treponema pallidum, emerging types of virus and parasitic infections are continuously confirmed to be related with transfusion. New strategies are also introduced in blood screening.Objective:To compare the effect of Enzyme-linked immunosorbent assay (ELISA) and nucleic acid amplification testing (NAT) on screening Hepatitis B virus (HBV), Hepatitis C virus (HCV) and Human immunodeficiency virus (HIV), assess the application value of NAT in blood donors screening and provide references for the future general usage of NAT.Method:68344 free blood donators who visited Chengdu Blood Centre from September 2010 to March 2011 were objects of our study. Blood sampled from antecubital vein and plasma was separated after anticoagulation by EDTA. HBV, HCV, HIV and treponema pallidum were determined by ELISA with domestic and imported reagent. Levels of Alanine transaminase (ALT) were also measured in the samples. For blood samples with negative reaction by ELISA, each 6 mixed seronegative samples were screened by NAT testing on COBAS s 201 System (Roche diagnostics, COBAS(?) AmpliPrep(?) / TaqMan(?) System) for HBV DNA, HCV RNA and HIV RNA. If the mixed samples were positive after determined, single sample was determined. The reactive samples were further discriminated by COBAS TaqScreen tests.Results:The results of ELISA showed that there were 94.84% (64820/68344) of samples with negative plasma virus and 5.16% (3524/68344) of samples with positive plasma virus after determined by domestic and/or imported reagents. In 3524 samples with negative plasma virus determined by ELISA, there were 22.36% (788/3524) samples with positive HBsAg, 21.03% (741/3524) samples with positive anti-HCV, 5.62% (198/3524) samples with positive anti-HIV, 22.59% (796/3524) samples with anti-TP, and 28.41% (1001/3524) samples with ALT≥40U/L. 22139 samples with negative reaction by ELISA were determined by NAT, and the results showed that there were 31 mixed samples with positive reactions by NAT. 19 samples with positive plasma virus were found after detection of each sample of mixed samples, the yield ratio was 0.086% (19/22139). There were 16 samples with positive HBV DNA, and 3 samples with positive HCV in 19 samples after identified by clinic centre of ministry of health.Conclusion :Nucleic acid amplification testing is sensitive and can reduce the yield rate of ELISA, which can be used as a complementary detection of blood samples with negative ELISA in blood screening in large scale of blood donation without payment.