University of Texas Health Science Center at Houston, Houston, Texas, USA Houston, Texas, United States
Background/Case Studies: Providing fresh, phenotype-matched red cell units (RCUs) for exchange transfusion in sickle cell disease (SCD) patients is resource-intensive and costly. However, the clinical implications of using older RCUs in this context remain unclear. This study evaluates the safety and outcomes of an innovative mixed-age red cell unit strategy—using equal parts fresh (< 10 days) and older (10–21 days) units—for routine exchange transfusions in sickle cell disease.
Study
Design/Methods: This retrospective single-center study (April 2019–May 2025) evaluated routine (6–8 weekly) outpatient red cell exchange (RCE) using mixed-age RCUs for stroke prevention and vaso-occlusive crises in SCD. Key outcomes included alloimmunization, post-exchange complications, post-procedure hematocrit and hemoglobin S (HbS) levels, rehospitalization rates, and mortality.
Results/Findings: A total of 102 patients (57 female, 45 male), aged 22–71 years, underwent red cell exchange with a median of 9.5 mixed RCUs (Interquartile Range, i.e., IQR 5–14) per procedure. Median post-procedure hematocrit was 26% (IQR 22–32) and HbS 9.75% (IQR 3.1–17.5). Alloimmunization affected 27% patients (Table 1), with only 4% developing new antibodies [nonspecific IgG, anti-Kp(a), anti-Js(a), and anti-RH7] during the course of study. Post exchange complications occurred in 8.8% of the cases, mainly allergic reactions (67%) and hemodynamic instability (33%), with no TRALI, bacterial contamination, or electrolyte imbalance noted. Repeat hospitalizations occurred in 24% of the patients, mainly due to pain crises (24%) and acute chest syndrome (4%), with few cases of silent stroke (1%), seizures (2%), and pulmonary embolism (2%). One patient died from sepsis and multiorgan failure. Moreover, improved blood availability and minimized waste enabled our lab to save about $2,000 in blood product costs per exchange procedure.
Conclusions: Mixed-age RCUs appear safe and cost-effective for routine RCE in SCD. Our findings show lower alloimmunization and readmission rates compared to reported data. Optimal use should be guided by clinical factors, including treatment urgency, special transfusion requirements, potential complications, and inventory availability. Study of using mixed-age RCUs in long-term simple RBC transfusion will further enrich our experience in SCD management.
