(P-TS-53) Frequency of febrile non-hemolytic and delayed serologic transfusion reactions during a sixteen-year period at a large quaternary academic medical center

Febrile non-hemolytic transfusion reaction (FNHTR) and delayed serologic transfusion reaction (DSTR) are not uncommon complications occurring after red blood cell (RBC) transfusions.  Since 2008 our institution has implemented and participated in the National Healthcare Safety Network Hemovigilance Module (NHSN) to monitor transfusion-associated adverse events. 

Study

Design/Methods: In this retrospective study, the incidences of FNHTR and DSTR due to RBC transfusion from 2008 to 2023 were reviewed. These were trended over time and changes in the frequency of these reactions were analyzed for statistical significance. The demographic characteristics and related histories of the involved patients were also analyzed

Results/Findings: A total of 371,768 products were transfused in the sixteen year period (annual mean 23,236) with a total of 2,000 transfusion reactions recorded (annual mean of 125 reactions). Of these, there were 930 cases of febrile non-hemolytic transfusion reactions (FNHTR) (46.5%) and 492 cases (24.6%) were delayed serologic transfusion reactions (DSTR). The rate of FNHTR significantly decreased from 71.2% in 2008 to 46.2% in 2023 (p=0.0002). The highest number of RBC transfused in the sixteen years occurred in 2016 with a total number of 26,533 units transfused. In this year, there were 170 transfusion reactions (0.6% of total RBC transfused), which was the highest in the sixteen years under study. Seventy-five of these cases were FNHTR (44.1%) but this proportion was still lower than 2008 and statistically significant despite the total number of transfusion reactions being higher (p=0.005). In the same year, 43 cases were DSTR (25.3%) which represented a relative increase from 2008 (p=0.013). Overall, FNHTR rate showed a gradual reduction over the study period, with the only peak occurring in 2014 to 67.6% but this was still lower than that in 2008 (p=0.57). In contrast, the rate of DSTR steadily increased and tripled from 10.2% in 2008 to 38.7% in 2023 (p< 0.001) with the only decrease occurring in 2013 to 15.8% (p=0.22).

Conclusions:

Review of the RBC-transfusion reactions for the last sixteen years suggests a gradual reduction in FNHTR and a steady increase in DSTR incidences.  This apparently opposite rates cannot be explained by changes in reporting because DSTR are resulted by the issuing Blood Bank. Immunological processes mediating both type of reactions are distinct, one being mediated by antibody formation (DSTR) and the other mediated by release of pyrogenic mediators produced by immune cells, i.e. leukocytes, found in the RBC unit or preformed during storage (FNHTR). A better understanding of observed trends in FNHTR and DSTR incidences is needed.