INTRODUCTION Nucleic acid testing (NAT) is a molecular technique for screening blood donations to reduce the risk of transfusion transmitted infections (TTIs) in the recipients, thus providing an additional layer of blood safety. It was introduced in the developed countries in the late 1990s and early 2000s and presently around 33 countries in the world have implemented NAT for human immunodeciency virus (HIV) and around 27 countries for hepatitis B virus (HBV). NAT technique is highly sensitive and specic for viral nucleic acids. It is based on amplication of targeted regions of viral ribonucleic acid or deoxyribonucleic acid (DNA) and detects them earlier than the other screening methods thus, narrowing the window period of HIV, HBV and hepatitis C virus (HCV) infections. NAT also adds the benet of resolving false reactive donations on serological methods which is very important for donor notication and counseling. This study is one such effort to nd the best way to diagnose. Large number of blood transfusions are carried out globally to save countless lives,() but unsafe practices risks the recipient of transfusion transmittable infections((TTI'S). TTI's can be reduced by improving donor selection, donor awareness regarding TTI and implementing sensitive screening tests.() In India, it is mandatory to test each donated unit of blood for markers of HIVI and II, HBV, HCV, malaria and syphilis.() Currently, in India all the blood donations are screened for various infectious markers using ELISA or rapid methods. TTIs can be responsible for causing considerable burden on the health status and economy of the country.() Hence there is need to introduce better methods for testing blood units. Even after being seronegative the blood transfusions are still at risk of transmitting infections. In order to reduce the residual risk sensitive screening tests are needed and as a result NAT has been considered. In India NAT testing is not mandatory but many private blood banks and hospitals and state Governments of few states have started implementing NAT for blood safety.(, ) It increases the possibility of identifying the infection in window period and thus reducing the residual risk of TTIs.() NAT is highly sensitive and specic for viral nucleic acids and is based on amplication of targeted regions of RNA and DNA and thus is the technique of choice. By early detection than serology, the window period of HIV, HBV and HCV infections narrows. But the issue of higher cost accounts for its limited use especially in developing countries.() The present study is designed to understand the role of NAT in detecting the risk acquiring TTIs as compared to conventional methods currently in use for detection of HBV, HCV and HIV infections amongst blood donors. MATERIALS AND METHODS The present study was carried out at blood bank, A.J Institute of medical Sciences, Mangalore. It was a two years (July 2008 to December 2010) non-interventional, retrospective, observational study. The blood collections were carried out from the voluntary donors at outdoor blood donation camp and in-house blood bank as well as from replacement donors at blood bank. Trained personnel carefully selected the donors for donation after a complete physical examination and satisfactorily answering the donor's questionnaire according to blood donor selection criteria and guideline from drug and cosmetic act and NACO. On completion of blood donation, the units were screened for the ve commonest TTIs namely HIV I & II, HBsAg, HCV, syphilis and malaria. Screening test ELISA and Rapid Kit were used for HIV I & II, HBsAg, HCV. Screening test Rapid Kit and Peripheral smear were used for Malaria. VDRL is used for screening Syphilis. The reactive sample was retested in duplicate before considering it seropositive. Seropositive blood bags were discarded. All non-reactive samples are sent to Bowring and Lady Curzon Hospital, Bangalore for conrmation testing by NAT technique for HIV I & II, HBsAg, HCV to reduce the risk of transfusion transmitted infections (TTIs) in the recipients, thus providing an additional layer of blood safety. The data were recorded on specially formed proforma, the recorded data were tabulated and analysed. For comparing NAT and Elisa as suggested by the statistician Cohen's Kappa Coefcient, statistical test is used. RESULTS Our study was a 2 years non-interventional retrospective study and the data was collected from the Blood Bank. During the study period total of 3183 donors donated the blood. Out of 100 blood donors, all were voluntary donors. Out of the total donors 50 were females and rest that is 50 were Male. The age of the blood donors in the present study ranged from 20 - 50 years Out of the total 100 screened blood units 07 were seropositive for the transfusion transmitted infection. Among the 7 seropositive donors, 4 were positive for HBV infection and out of those 3 were HbsAg positive and 4 seropositive donor which was not detected by the serological test was detected by the NAT. Statistically using Cohen's COMPARISON OF ELISA AND NAT TECHNIQUES AMONG BLOOD DONORS Original Research Paper Dr Praveena Kumara* Assistant Professor, Department Of Medicine, A.j.institute Of Medical Sciences, Mangalore. * Corresponding Author General Medicine Nucleic acid testing (NAT) is a molecular technique for screening blood donations to reduce the risk of transfusion transmitted infections (TTIs) in the recipients, thus providing an additional layer of blood safety. It was introduced in the developed countries in the late 1990s and early 2000s and presently around 33 countries in the world have implemented NAT for human immunodeciency virus (HIV) and around 27 countries for hepatitis B virus (HBV). NAT technique is highly sensitive and specic for viral nucleic acids. It is based on amplication of targeted regions of viral ribonucleic acid or deoxyribonucleic acid (DNA) and detects them earlier than the other screening methods thus, narrowing the window period of HIV, HBV and hepatitis C virus (HCV) infections. NAT also adds the benet of resolving false reactive donations on serological methods which is very important for donor notication and counseling. This study is one such effort to nd the best way to diagnose. ABSTRACT KEYWORDS : Nucleic Acid Testing, Transfusion Transmitted Infections, Blood Transfusion VOLUME-8, ISSUE-10, OCTOBER-2019 • PRINT ISSN No. 2277 - 8160 • DOI : 10.36106/gjra 90 X GJRA - GLOBAL JOURNAL FOR RESEARCH ANALYSIS Kappa coefcient, it was noted that the strength of agreement between ELISA and NAT can be considered to be very good. DISCUSSION Blood transfusion is most important part of medical treatment and it's also associated with risk of transfusion transmitted infections (TTIs). Hence screening of blood bags is important to ensure safe blood transfusion. An effective donor screening, sensitive screening tests can reduce the risk of acquiring TTI's. CONCLUSION Blood Banks are likely to work more efciently if the NAT technologies are implemented which will help in intercepting potentially harmful infectious pathogens while continuing to provide on time blood availability for patients and to the hospital. As NAT implementation reduces the rate of TTIs, its implementation will gain more speed in many more countries as a valuable addition to existing safety efforts. REFERENCES 1. Jasani J, Patel V, Bhuva K, Vaihhani A, Patel H. Seroprevalence of transfusion transmissible infections among blood donors in a tertiary care hospital. Int J Biol Med Res. 2012;31:1423-5. 2. Bihl F, Castelli D, Marincola F, Dodd RY, Brander C. Transfusion-transmitted infections. Journal of translational medicine. 2007;5(1):25. 3. 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