Trends in the incidence of delayed hemolytic and delayed serologic transfusion reactions.

BACKGROUND: An increasing incidence of delayed hemolytic and delayed serologic transfusion reactions (DHTRs/DSTRs) has been seen at the Mayo Clinic since 1978. Recently, the average length of stay (LOS) for inpatients and the average number of red cell transfusions per inpatient (TPI) decreased, and the albumin and papain technique for RBC antibody detection was replaced by a polyethylene glycol technique. These changes may have affected the incidence of DHTRs/DSTRs.

STUDY DESIGN AND METHODS: The diagnoses of DHTR and DSTR made at the Mayo Clinic from 1993 through 1998 were reviewed. These data were compared with previously published Mayo Clinic data from 1980 through 1992. The LOS for inpatients and the average TPI were also obtained from hospital data.

RESULTS: The incidence of DHTR/DSTR increased from 1 in 1899 in 1980 through 1992 to 1 in 1300 in the 1993 through 1998 period (p < 0.05). Similarly, DSTR increased from 1 in 2990 in 1980 through 1992 to 1 in 1612 in the 1993 through 1998 period (p < 0.05). The incidence of DHTR showed a trend toward decrease, from 1 in 5405 in 1980 through 1992 to 1 in 6715 in 1993 through 1998. No alloantibody specificities were statistically associated with DHTRs in 1993 through 1998, unlike in the 1980 through 1992 period. Moreover, the incidence of Jka antibodies increased in 1993 through 1998, while the incidence of other alloantibodies remained stable. Average LOS and TPI declined by 24.5 percent and 8.8 percent, respectively, between the two periods.

CONCLUSION: Recently, a trend toward a decrease in the incidence of DHTR and a significant increase in DSTRs has occurred at the Mayo Clinic. These changes are most likely due to a combination of factors, including a decrease in average LOS and the adoption of the polyethylene glycol antibody detection system.