Nucleic acid testing in Colombian blood banks (2018-2024): Implementation, yield estimates and implications for safer transfusion policy.

Background and objectives: Colombia has a population of 52.6 million inhabitants and a blood donation rate of 26 donations per 1000 inhabitants. The 84 blood banks in the country collect approximately 1 million donations annually, which are mandatorily screened for human immunodeficiency virus (HIV), hepatitis B virus (HBV), hepatitis C virus (HCV), human T-lymphotropic virus (HTLV), Trypanosoma cruzi and Treponema pallidum. Currently, 95% of donations are screened using chemiluminescence and the remaining using enzyme-linked immunosorbent assays (ELISA). However, nucleic acid testing (NAT) is not mandatory for any infectious agent. The aim was to assess the progress in the voluntary implementation of NAT for HIV, HBV and HCV in blood banks.

Materials and methods: Data from the National Haemovigilance Information System were analysed between January 2018 and December 2024, including the total number of donations collected and the screening results obtained through chemiluminescence, ELISA as well as NAT in blood banks that voluntarily adopted this technology.

Results: During the study period, a total of 6,435,189 blood units were collected, of which 6.9% were screened using NAT. The data revealed 10 undetected immunological windows with conventional techniques: four for HIV, three for HBV and three for HCV. It is estimated that the universal implementation of NAT would have identified 135 additional infectious units, potentially preventing at least 83 infections in recipients.

Conclusion: The progressive implementation of NAT in Colombian blood banks has demonstrated the presence of immunological windows undetectable by conventional serological techniques, highlighting the potential risk for blood recipients. These findings underscore the need to accelerate NAT adoption and consider making it mandatory in 100% of the country's blood banks.