Posttransfusion platelet count increments after ABO‐compatible versus ABO‐incompatible platelet transfusions in noncancer patients: an observational study

BACKGROUND: Major incompatible platelet (PLT) transfusions have been associated with inferior posttransfusion PLT count increments compared with ABO‐compatible transfusions. However, most studies to date have been small and involved hematology/oncology patients. STUDY DESIGN AND METHODS: We conducted a prospective observational study in predominantly nononcologic patients to determine whether ABO‐compatible (defined as ABO identical and minor incompatible) PLT transfusions resulted in superior posttransfusion PLT count increments. We collected data on consecutive inpatients at Hamilton General Hospital receiving a PLT transfusion during a 50‐month period. We compared the absolute count increment (ACI) and corrected count increment (CCI) values in ABO‐compatible versus incompatible PLT transfusions. Linear regression was performed to adjust for factors potentially affecting the posttransfusion PLT count response. Univariate models were applied to each explanatory variable with p values of less than 0.10 considered potentially significant. Multivariate models were applied to all potential explanatory variables of interest. p values of less than 0.05 were considered significant. RESULTS: A total of 1030 transfusions were included in the primary analysis, 73.7% of which were ABO compatible. The median ACI was 35 (interquartile range [IQR], 18‐55) for compatible transfusions versus 31 (IQR, 13‐51) for incompatible transfusions (p = 0.1480). The median posttransfusion CCI (n = 686) was 18.6 (IQR, 10.2‐28.4) for compatible transfusions versus 15.2 (IQR, 4.7‐25.7) for incompatible transfusions (p = 0.0499). CONCLUSIONS: ABO‐compatible transfusions in nononcologic patients are associated with a significantly better CCI although the observed difference is small (approx. 20%) and may not be clinically significant.