Hold on to your units: Quality of red cell concentrates is only affected after multiple transient warming events.

Abstract

Background: Cryopreserved red cell concentrates (RCCs) glycerolized using a high glycerol (40%) method can be stored below -65°C for up to 30 years; however, units may be inadvertently warmed above -65°C due to freezer failures, human errors, or routine inventory management. RCCs known to have experienced transient warming events (TWEs) or storage temperatures ≥-65°C are frequently discarded.

Study design: Six groups of ABO/Rh matched RCCs were pooled-and-split (n = 9), glycerolized using the ACP 215 (Haemonetics), and frozen. Three types of TWEs were performed: (1) "Fast" TWEs (warming at room temperature [RT] to -25°C), (2) "Slow" TWEs (exposure to -25°C for 2 h), and (3) "Thaw" TWEs (single warming to RT). Units (n = 6) were exposed to 0 (control), 1, 10, or 30 "Slow" or "Fast" TWEs. RCCs were deglycerolized using the ACP 215, stored at 1-6°C, and tested at 0, 1, 7, and 14 days post-deglycerolization for red blood cell (RBC) quality.

Results: No significant differences among RCCs over hypothermic storage were found when exposed to "Fast" or "Slow" single or "Thaw" TWEs, although a significant decrease in the quality of RCCs was observed when units were subjected to 10 or more "Fast" or "Slow" TWEs.

Discussion: Our data suggests the single TWEs examined in this study do not significantly impact the quality of RCCs post-deglycerolization. Based on these observations, TWE exposure considerations should be made on a unit-by-unit basis, with additional policy support for unit retention.