Utility of grey zone sample testing strategy for transfusion transmittable infections to improve blood safety of a tertiary care center

Background: Grey zone samples with optical density (OD) lying between cut-off OD and 10% below the cut-off OD were identified during routine transfusion transmissible infectious disease screening by Enzyme-linked immunosorbent assay and its application in blood transfusion services. Materials and Methods: The present is an observational study where blood donors samples have been screened by performing repeat ELISA testing on Grey zone samples in duplicate at the A.D Gorwala Blood Centre, Karamsad between January 2018 to December 2020. Results: A total of 20560 blood donors were screened during the study period, out of which 12 blood donors were found to be in grey zone. On repeat testing of these, 02 were found to be reactive and 01 was found to be in grey zone again. Conclusion: Appropriate quality control measures can improvise the current screening methodologies in TTIs of blood bank centres, especially in resource constrained settings, where the NAT technology is not financially feasible.