Effects of blood storage for one tube osmotic fragility test in normal and thalassemia trait

Abstract

One tube osmotic fragility test (one tube OFT) is the screening method for thalassemia trait detection. Red cells of thalassemia trait are less fragile than normal in hypotonic solution. There are many factors that influent the result of the test. Aim of this study was to investigate the effects of temperature, time and anticoagulant for blood storage on one tube OFT. Blood samples were collected from 20 volunteers consisted of 10 normal individuals and 10 subjects with thalassemia trait. Each blood samples were collected in 2 EDTA and 2 heparin tubes and then divided into 2 groups. The first groups of EDTA and heparin tubes were stored at room temperature and the second groups were stored in refrigerator that each blood sample was determined by two minute OFT, five minute OFT and overnight OFT at 0, 6, 24, 30, 48, 54, 72, 78 and 96 hours, respectively. The means of osmotic fragility results were not significant different (P-value > 0.05) between using EDTA and heparin but they were significant different when compared at each temperature and each hour of storage (P-value < 0.05). In conclusion, one tube OFT can be performed on EDTA or heparinized blood. The blood should be determined within 15 hours at room temperature or within 54 hours at refrigerator storage by either two minute OFT or overnight OFT. However for five minute OFT, the blood samples should be determined within 15 hours at room temperature or within 30 hours at refrigerator storage.

Keywords : one tube osmotic fragility test, thalassemia trait, anticoagulant, blood storage