Usefulness of frozen-thawed-deglycerolized red blood cells as quality control materials for red blood cell deformability test

Background : The red blood cell (RBC) deformability test is a useful method for measuring the ability of RBCs to adapt their shape to the flow conditions. Using this test, several investigators have shown the relationship between RBC deformability and numerous clinical conditions. For the quality control (QC) of RBC deformability test, we evaluated whether frozen-thawed-deglycerolized RBCs can be used as QC materials. Methods : Packed RBCs were frozen with 40% (wt/vol) glycerol and stored at -80°C for 3 months. For 10 different frozen RBC panels, RBCs were thawed, deglycerolized and stored at 4°C for 4 weeks. Using microfluidic ektacytometer, we measured RBC deformability of the thawed RBCs. The stability of thawed RBCs was tested once a day for 28 days of storage time and was analyzed by simple regression analysis. The precision of the test using thawed RBCs was analyzed for 7 days of storage time by calculation of CV values of intra-assay (10 measurements/assay) and betweenday measurements. Results : Frozen-thawed-deglycerolized RBCs were stable for 1 week. Within-run and betweenday precisions of the RBC deformability test during 7 days of storage of thawed RBCs were 1.4-2.9%, and 1.9-2.8%, respectively. Conclusions : Frozen-thawed-deglycerolized RBCs used in RBC deformability test showed satisfactory within-run and between-run precisions and stability for one week after thawing, and may be used as QC materials for this test.