The study was planned to determine the incidence and analyze how various epidemiological factors tend to be associated with delayed adverse donor reactions (ADR).

The prospective observational study was conducted in Department of Transfusion Medicine of tertiary care hospital from January to December 2019. Eligible blood donors were observed for any adverse reactions after 15 minutes of removal of phlebotomy needle. Further, telephonic calls were made to each enrolled blood donor on day-2 and day-7 of the whole blood donation. For each day, two calls were made at an interval of 4 hours before declaring the participant to be non-responder.

A total of 1540 (84.1%) blood donors responded on day-2 and 1610 (87.9%) responded on day-7 of follow-up. Total 180 (11.2%) blood donors experienced delayed ADRs. Two donors (1.1%) experienced on-site while 178 (98.89%) reported off-site delayed ADRs when followed-up telephonically. The commonest delayed ADRs reported were bruise (n=72; 30.9%), arm-pain (n=61; 26.2%) and generalised weakness (n=44; 18.9%). Female donors (27.3% vs. 11.2%; P=0.004), first time donors (15.2 vs. 9.9%; P=0.002), donors with low body-weight (range of 45–60kg; 15.9% vs. 11.5% vs. 6.1%; P=0.011) and body mass index<18.5 (24% vs. 12.5% vs. 9.7% vs. 11.3%; P=0.028) experienced more delayed ADRs.

Blood donors do experience delayed ADRs but these are not reported to the blood centers as these are usually mild. However, it is important to capture these delayed adverse donor reactions and report it to National Hemovigilance Program so that strategies can be formulated to prevent their occurrence and recurrence.