By Dr Prashant Pandey, Consultant, Department of Transfusion Medicine & Blood Bank, Jaypee Hospital, Noida
Blood transfusion may lead to serious clinical consequences for the recipient, if the transfused blood is not safe. In a country like India with more than 1.2 billion population, inspite of continuous improvement in criteria of donor selection and better screening methods for transfusion transmitted viral diseases (TTVDs), the transmission risk of TTVDs still remains a major concern here.
Challenges so far
The prevalence of infections like HIV, Hepatitis C (HCV) and Hepatitis B (HBV) amongst the general population is noted to be 5.7 million, 12 million and 40 million, respectively. In India, the burden of Hepatitis B carriers is approximately 10 % of the global burden which is unquestionably high. Amid these high statistics of disease burden, the transfusion of safe blood is the biggest transfusion challenge in India.
The other reason why the âsafe blood transfusionâ has become a big challenge in India is the consistent lack of repeat voluntary blood donations. Thus, it is not only the high burden of HIV, HBV and HCV in general population but also the absence of safe repeat voluntary blood donors in Indian society has made bloodÂ transfusion a challenge, especially in patients who require multiple blood transfusions at regular intervals.
The prevalence of HCV amongst Thalessemia patients is estimated to be as high as 45% while two other studies from the Western India have estimated its prevalence as 16.7% and 17.5%, respectively. The prevalence of transfusion transmitted HBV and HIV has been estimated as 2% each.
Towards achieving the ânear zeroâ risk of TTVDs
In the last one decade, voluntary blood donation in India has improved significantly but still the proportion of repeat blood donation is very small. It is still posing challenges to achieve ânear zero riskâ of transmission of TTVDs only with ELISA (Enzyme Linked Immunosorbent Assay), an indirect method of testing of blood donors where we need to wait for the production of viral specific antibodies (or release of viral antigens). The production of the viral specific antibodies (or release of antigens) to reach the detection limit takes several weeks from the date of initial infection. During this period which is called as âserological window periodâ, the risk of transmission of viral infections is very likely. None of the biological system is 100% effective and could bring the transmission risk of TTVDs to âzeroâ.
ID-NAT â Need of the hour
To reduce the transmission risk of TTVDs to ânear zeroâ, nucleic acid amplification testing (NAT) techniques have been implemented in major countries worldwide. This has remarkably reduced the window period of detection of viral infections and is equally able to detect both window-period infections and chronic carrier with low viremia. The state when ELISA demonstrates negative result while NAT shows positive result is known as âNAT yieldâ.
Today, there are very few blood centres in India that are regularly performing NAT testing and are sharing their data and experience of NAT testing at various scientific forums and meets worldwide. The NAT testing in India has been praised extensively in terms of interdiction of TTVDs in serological window period wherein the data has demonstrated a very high yield rate of 1 in 1528.
âAbsence of voluntary blood donors has made blood transfusion a challenge, especially in patients who require multiple blood transfusions at regular intervals”
The other important aspects which can further enhance the transfusion safety are the real-time reporting of transfusion incidents and to make a uniform policy for transfusion transmitted disease testing countrywide. India needs to have an effective hemovigilance program for the reporting of transfusion incidents and it should be made mandatory to all. Thus the four aspects which can help to achieve the ânear zeroâ risk of blood transfusion are as follows:
â¢ To increase the repeat voluntary blood donation
â¢ NAT testing of blood donors
â¢ Real-time reporting of blood transfusion incidents
â¢ Effective hemovigilance program at country level
The Department of Blood Bank & Transfusion Medicine at Jaypee Hospital has a state-of-the-art facility for the testing of blood donors with both serology basis enhanced chemiluminescence method and ID-NAT for the detection of viral genomes. We also have a huge in-house donor pool of eligible blood donors who have voluntarily donated blood at various occasions and will further help to enhance the safety of blood transfusion.
To enhance the accuracy, safety and efficiency, the transfusion services at Jaypee Hospital has a global standard for labelling of blood components empowered with an Information Standard for Blood and Transplant (ISBT-128). It is the global standard for the terminology, identification, coding and labelling of blood products.