Exposure of red blood cell concentrates to temperatures below 0°C for a short period does not alter in vitro quality

Background To guarantee the quality of red blood cell (RBC) transfusion, RBC concentrates (RCCs) are stored at 4±2°C. Deviations from this specification can alter the RBCs. Although the exposure to higher temperatures is well documented, the exposure to subzero temperatures has been less investigated. Materials and methods RCCs (prepared from top-bottom kits and stored in saline-adenine-glucose-mannitol - SAGM) accidentally exposed to temperatures below 0°C were investigated in two regional blood services in Switzerland; Case 1: 1 h 52 min below 0°C (minimum of −5.7°C), and Case 2: 3 h 19 min below 0°C (minimum of −0.9°C). In case 1, 5 exposed and 5 unexposed RCCs were visually inspected for hemolysis or other alterations. Hemolysis was quantified in the 5 exposed RCCs and one control. In Case 2, 71 RCCs were analyzed at the time of the incident and at day 42 for hematological parameters and hemolysis. Ten RCCs were followed weekly for glucose, lactate, potassium levels and deformability. Results Under these conditions no signs of out-of-specification hemolysis or RBC damages were observed. Nevertheless, a higher hemolysis was reported in 4-day-old RCCs exposed to subzero temperature compared to existing and age-matched controls. Storage lesions were equivalent to those of unexposed RCCs and to values reported in the literature. Discussion The two present real cases of RCCs exposure to temperatures below 0°C did not show damage to RBCs over storage. Even though the present work did not investigate the limits of RBCs sensitivity to cold temperature, it provides indications on the capability of RCCs to resist such type of storage deviation.