In a study conducted to demonstrate the necessity and feasibility of Nucleic Acid Testing (NAT) testing in an individual donor format to improve the safety of the blood supply, the All India Institute of Medical Sciences (AIIMS) has identified significant transfusion transmitted viral risk in India, with NAT significantly reducing the detection 'window period'.
Further to a diktat from the Supreme Court, the Indian Government made blood screening mandatory in 2000, given the high prevalence of hepatitis and HIV in India (e.g. there are approximately 43 million hepatitis B carriers in India). However, existing standard of care (ELISA serology testing) in India continues to allow a 'window period' between viral infection and viral detection. Unlike countries where compulsory NAT has ensured the safest blood supply possible, NAT is still not mandatory in India.
Keeping this in mind, AIIMS decided to undertake the 'AIIMS NAT Experience' study to identify the risk of HIV and hepatitis transmission from blood transfusions in an India government setting, and like other countries in Asia Pacific the ability of NAT to intercept and prevent this risk. Study identified additional transfusion transmitted viral risk by interception of infectious samples by NAT.
The pilot study, conducted on 5,818 donor samples for the presence of HIV, hepatitis B and C, detected the presence of five NAT positive and sero-negative cases. This equates to a risk of 1:1,164 for a missed sample, and is consistent with other studies conducted in Asia Pacific (eg China and Taiwan) and Africa (eg South Africa) where there are high prevalence of the viruses.
Dr Kabita Chatterjee, Faculty in-charge, Blood Bank at AIIMS, New Delhi and principal coordinator of the study said, "We compared NAT tests with the standard testing methods in use and found that with the current testing methods it is difficult to identify the viruses during the 'window period', where the virus is still multiplying in the body but the donor may unknowingly donate infected blood. Moreover, each bag of donated blood collected can be transfused in up to three patients. With 7.4 million blood donations collected annually in India, that equates to more than 6,000 donations potentially missed with existing testing technologies, and up to 20,000 patients and families being adversely affected."
Dr Kabita further added, "A new molecular technology based on the principle of Transcription Mediated Amplification (TMA) enables magnification of even very low amounts of viral genetic material, and allows for individual donation testing (IDT) to maximize test sensitivity. Given (1) the frequent presence of low viral concentrations in many blood donation samples and (2) the high viral prevalence in the Indian setting, TMA in IDT format is ideal to ensure maximum possibility of viral interception."
The study also confirm the feasibility of NAT testing in India, both in the government and private setting. As a matter of fact, NAT is already available in India. Dr Anand Deshpande, consultant, Transfusion Medicine, P D Hinduja Hospital, Mumbai said, "NAT is part of the routine testing in 12 blood centres across India such as AIIMS, Hinduja Hospital, RML Hospital, Apollo Hospital and others. Implementation of NAT is an important step forward in the prevention of transfusion transmission infections in India. In fact, the government and various blood banks have already planned adoption and implementation of NAT to increase the availability of a safer blood supply."
Dr Kanjaksha Ghosh, director, Institute of Immunohaematology, Mumbai said, "The 'NAT Experience' study has highlighted the need for a patient centric approach to blood safety by making tests like NAT mandatory in India and to ensure we have the safest possible blood supply in India."