Multiplex Real-time RT-PCR Assay for Transfusion Transmitted Viruses in Sero-negative Allogeneic Blood Donors: an Experience from Southern Pakistan

Background: Blood transfusion safety commences with healthy donor recruitment. The threat of transfusion transmitted infections is greatly minimized by serological tools but not entirely eliminated. Recently, nucleic-acid testing for blood donor screening has virtually eliminated this jeopardy.

Methods: This prospective study was conducted from February 2015 to February 2016. Samples from seronegative donors were run on multiplex assay (Cobas, S-201 system platform, Roche) in a batch of six [MP-NAT]. In case of reactive pool, tests were run on every individual sample [IDNAT].

Results: Of 16957 donors, 16836 (99.2%) were replacement donors and the remaining 121 (0.7%) were voluntary donors, with a mean age of 29.09 ± 7.04 years. After serologic screening of all 16957 donors, 955 (5.6%) were found to be reactive; 291(1.71%) were reactive for hepatitis-B surface antigen, 361 (2.12%) for antibody to hepatitis C virus (anti-HCV), 14 (0.08%) for antibody to human immunodeficiency virus, 287 (1.69%) for syphilis and 2 (0.01%) for malaria. 14 (0.08%) NAT reactive donors were identified after testing the 16002 seronegative donors, with an overall NAT yield of one reactivity out of 1143 blood donations; 10 donors for HBV-DNA (HBV NAT yield-1:1600) and remaining 4 for HCV-RNA (HCV-NAT yield-1:4000). None were HIV positive.

Conclusion: NAT has improved the safety attributes in blood products. Although the positivity rate for NAT testing is low but in view of the high prevalence of transfusion transmitted infections in our country, we recommend the parallel use of both serology and NAT screening of all donated blood.