Transfusion Of Thawed Rare Red Blood Cell Units In Finland
Authors: Juvonen Eeva , Sareneva Inna , Haimila Katri , Korhonen Anu Elina , Sainio Susanna 
Published: October 2019

The Finnish Red Cross Blood Service performs blood grouping of all blood donations in Finland and serves as a national reference laboratory in pre-transfusion testing of patients. In addition to ABO and RhD blood groups, other Rh antigens and K antigen are also determined from all red cell units. The antigens of JK, FY, and MNS blood group systems are analyzed from selected donors. The extensive donor typing procedure includes antigens from KEL, LW, LU, CO, DO, DI, YT, GE and CROM blood group systems, performed either serologically or by genotyping. Patients negative for a high frequency blood group antigen present a challenge for transfusion laboratories. A blood group is considered rare if the prevalence is 1:1000 or less, with the most common rare phenotypes in Finland being LWa neg, Jk:-3 and Pk. To ensure the availability of matching blood for patients with a rare blood group, we started a freezing program of rare blood in Finland with Haemonetics ACP 215 process in April 2010. The system is closed, therefore after thawing the units are safe for use for 7 days. 18 blood groups which were included in the program were determined based on the known rare blood groups in the Finnish population. Blood groups which are globally rare but more common in Finland, such as Jk:-3 and LWa neg, are represented in our storage and also available internationally. The aim of the present study was to analyze the status of the freezing program of rare red blood cells in Finland. For the analysis we asked the transfusion data of rare red blood cell units delivered to 10 national and 2 international hospitals. Results: In 2010-2012, altogether 204 units of rare blood were stored, including units of all the predefined rare phenotypes except Vel neg. With the exception of Vel neg, Hrs neg and Oh blood groups, we have been able to meet the need for rare blood in Finland using Finnish donors. Altogether 55 units have been thawed and distributed to 27 adult patients. The indication was delivery in 3 cases, surgery in 6 cases, and chronic anemia in 4 cases. For the present analyses the transfusion data of 49 units was available. The data of 6 Coa neg units is missing. Altogether 22 / 49 (45%) of the units were transfused. In 14 cases the blood was transfused to the patient it was intended for, and in 8 cases to another patient, 27 units were discarded. There were no transfusion associated complications. The hemoglobin response was evaluable in 7 patients. In 4 patients with a chronic anemia the median blood hemoglobin response per a unit was +8 g/l, range +2 - +16 g/l. In 3 patients with blood loss during an operation the median increase in blood hemoglobin value was +7 g/l per unit, range +4 – +12 g/l. Conclusions: Compared to the common 24 hour eligibility of thawed red cell units, our units valid for 7 days are preferable in countries like Finland with long distances and in international rare blood deliveries. We have been able to offer rare blood to Finnish patients. The hemoglobin response was reasonable and there were no transfusion associated complications. Our next challenge will be to recruit Finnish blood donors with different ethnic backgrounds (eg. immigrants) and identify their rare blood groups. We have already expanded our program to include rare combinations of common blood groups.

Disclosures:
No relevant conflicts of interest to declare.