UTILITY OF MINI-POOL NAT STRATEGY FOR IMPROVING BLOOD SAFETY BY DETECTING OCCULT HEPATITIS B VIRUS INFECTION : A 5 YEAR STUDY

Abstract

Introduction: The prevalence of transfusion transmitted infections (TTIs) is high in India. The aim of our study was to evaluate the sero-prevalence of TTIs using Nucleic acid technology (NAT) and detection of Occult Hepatitis B virus infection by Minipool NAT Strategy. A total of 89,639 units of blood donated at Dhanvanta Materials and Methods: ri Voluntary Blood Bank, Rajahmundry during the period from January 2012 to July 2016. The sero-prevalence for HIV, HBV and HCV was tested by 4th generation ELISA. Only sero-negative samples were tested on mini pool nucleic acid test (MP-NAT) to detect HIV1, HIV2, HCV and HBV viral nucleic acids. Combined NAT yield was calculated and compared the NAT yield with MPX test and MPX V2.0. We also evaluated the optical density (OD) values of ELISA for MP-NAT reactive donor samples to evaluate the efcacy of NAT in detecting window period cases. The Results: overall sero-prevalence of TTIs was 2.41% and HBV was predominantly present (66%). Total 29 ELISA negative blood donor samples were found reactive on NAT. All NAT reactive donors were of HBV only. Out of 29 cases, 12 were detected by MPX test from 26,008 donations and 17 by MPX V2.0 from 25,619 donations, providing NAT yield of 1:2169 and 1:1507 respectively. OD and Signal cut off values of ELISA for NAT reactive samples were found to be much below extended grey zone value (<0.3). Additiona Conclusion: l testing of nucleic acids by MP-NAT in combination of mandated primary serology by ELISA provides 99.99% of safe blood to needy patients; thus signicantly reduces the risk of TTIs by identifying the window period cases.