In vitro quality control analysis after processing and during storage of feline packed red blood cells units

During the storage of packed red blood cells (pRBC), packed cell volume (PCV), bacterial contamination and percentage of haemolysis [percentage of free haemoglobin (HGB) in relation to the total HGB] are important quality parameters. Both PCV and haemolysis are indicators of the cellular integrity of stored units. There are no published experimental studies that evaluated these parameters during storage of feline pRBC using SAGM (adenine, dextrose, mannitol and sodium chloride) as the additive solution. The present study aims to (1) evaluate the quality of feline pRBCs stored in SAGM; (2) test for the semi-closed system's suitability for use and risk of bacterial contamination; (3) establish the maximum storage time that may be appropriate to meet the criteria established by the United States Food and Drug Administration (US-FDA) guidelines for human blood banking; and (4) evaluate the need to calculate the percentage of haemolysis prior to the administration of units stored for more than 4 weeks. Four hundred eighty nine feline pRBC units were analyzed. Bacterial culture, PCV and percentage of haemolysis were determined within 6 h after processing (t0). One hundred and eighty units were re-tested for haemolysis and PCV after 29-35 days of storage (t1) and 118 units after 36-42 days (t2).

Bacterial contamination was not detected in any pRBC unit. Mean PCV at t0 was 52.25% (SD: ±5.27) and decreased significantly (p < 0.001) during storage to 48.15% (SD: ±3.79) at t1 and to 49.34% (SD: ±4.45) at t2. Mean percentage of haemolysis at t0 was 0.07% (SD: ±0.06) and increased significantly (p < 0.001) to 0.69% (SD: ±0.40) at t1 and to 0.81% (SD: ±0.47) at t2. In addition, 13.88% and 19.49% of pRBC units exceeded 1% haemolysis at t1 and t2, respectively.

According to the US-FDA guidelines for human blood banking that recommend a maximum of 1% haemolysis, the results of this study show that all feline pRBC units with less than 24 h of shelf life have low levels of haemolysis. However, units preserved up to 28 days can only be administered if tested for haemolysis before use, since 13.88% units exceeded the 1% limit. The semi-closed system was considered safe for use as bacterial contamination was not detected in any pRBC unit.