AABB2025: The Impact of Blood Storage Age and Red Cell Quality For Patients With Sickle Cell Disease

Recent studies indicate that the age and quality of stored red blood cells (RBCs) may significantly affect transfusion outcomes, inflammation and complications in patients with sickle cell disease (SCD). In the Tuesday morning session, Matthew S. Karafin, MD, from UNC Health Chapel Hill School of Medicine, emphasized the need for more targeted blood management strategies in this population. 

Karafin began by reviewing the United States Food and Drug Administration’s (FDA) requirements for unit quality. According to the FDA, stored blood must have a greater than 75% 24-hour post-transfusion recovery and less than 1% hemolysis in the bag.  

Between 2010 and 2020, extensive research explored how storage age affects patient outcomes. Although large trials found no significant differences in mortality across patient populations, none specifically included patients with SCD, he pointed out.  

“As you know, patients with SCD are a very different population from those in the ICU. We’re not transfusing them simply to correct anemia. We’re transfusing to prevent strokes and manage vaso-occlusive crises,” Karafin said. “They represent a unique and complex group for whom questions about blood storage age remain unanswered.” 

He presented findings from a 2019 survey demonstrating that more than 50% of clinicians already limit the storage age of blood units for patients with SCD, despite limited evidence. Karafin noted his institution does not routinely restrict storage age, and internal data showed that approximately one-third of transfused units were older than 30 days. 

Karafin and his colleagues conducted the Age of Blood Trial, a double-blind, randomized study that ran from 2017 to 2024 to analyze the effects of red blood cell storage duration in patients with SCD. The study was designed to compare fresh (less than 10 days) and older (30 days) stored units. Samples were collected from 26 adults before and after each transfusion to assess inflammatory markers, hemoglobin changes, iron levels, pain and infection rates.  

Findings from the study suggest that red cells stored for 30 days or longer may not be optimal for chronically transfused sickle cell patients. Karafin said the team set out to answer a simple but important question: “Does the age of the blood we transfuse make a difference for patients with SCD?”  

“What we found was striking,” he told attendees. “Patients who received older red cells showed higher inflammation, higher iron levels, and were more likely to experience infections and pain crises. It suggests that for this population, storage age really does matter.” 

Karafin concluded his presentation by highlighting the forthcoming RBC Impact Study, a large-scale observational initiative designed to explore how genetics and donor-related factors affect transfusion outcomes in patients with SCD.  

“The upcoming Impact Study will be critically important for this field. It will help us better understand how to identify the right blood unit for the right patient with SCD,” Karafin said.