Establishment Of Reference Interval Of Erythrocyte Osmotic Fragility(Scattering Turbidimetry) And Clinical Application Research

ObjectiveBy analyzing the distribution characteristics of erythrocyte osmotic fragility(EOF)measured by nephelometry in healthy people,the reference interval of EOF was established and its clinical application in thalassemia and donor screening was preliminarily discussed.MethodsFirstly,the performance of the detection system was evaluated according to the health standard;then the EOF of the remaining whole blood samples of 2451 healthy examiners was detected,and the biological reference interval was established according to its distribution characteristics and preliminarily verified;170 of them were tested by the traditional tube method,and the results of the two methods were compared;EOF,MCV(mean corpuscular volume,MCV),MCH(mean corpuscular haemoglobin,MCH)and thalassemia gene tests were carried out on the whole blood samples of 122 thalassemia screeners.The clinical application value of EOF in thalassemia screening was preliminarily evaluated based on the gene test results.300 blood samples from clinically qualified donors were collected for MCV,MCH,EOF,glucose6-phosphate dehydrogenase(G6PD)activity,thalassemia gene and G6PD mutant gene detection,and the application value of EOF in donor screening was preliminarily explored.ResultsThe high and low intra batch precision and total precision of automated nephelometry were 2.97%,1.69%,3.74%and 1.71%respectively;The background count was 0%,the carrying contamination rate was 1.49%,and the analytical performance of the detection system met the requirements of clinical application.According to its distribution characteristics,the reference interval of this laboratory was male>73%female>74%。Taking this as the boundary value of negative and positive,the negative compliance rate between the test results and the traditional test tube method was 96%and the positive compliance rate was 100%.There was no significant difference in the test resuts(P>0.05).When applied to screening for thalassemia alone,the sensitivity,specificity,positive expected value and negative expected value of EOF were 73%95%,81%and 91%,respectively;Combined with MCV and MCH,the sensitivity was 93%,the specificity was 83%,the positive predictive value was 64%,and the negative predictive value was 97%.The detection rates of thalassemia and G6PD Mutation Genes in blood samples of 300 donors were 11.3%and 6.67%,including 8 species thalassemia genotype-α3.7、αα、α4.2/αα、-SEA/αα、αWSα/αα、αCSα/αα、αQSα/αα、βCD41-42M/β、βIVS-II-654M/β and7G6PD mutation sites,c.519G>A,c.1388G>A,c.1376G>T,c.392G>T,c.95A>G,c.592C>T,c871G>A.The difference of MCV,MCH and EOF in the blood samples of donors with and without thalassemia gene was statistically significant(P<0.01),but the difference of G6PD enzyme activity was not statistically significant(P>0.05).There was no significant difference in MCV,MCH and EOF between with and without G6PD mutation gene(P>0.05),but there was significant difference in G6PD enzyme activity(P<0.01).ConclusionAutomated scattering turbidimetry is a new method to measure the osmotic fragility of red blood cells.The biological reference interval of this method was male>73%,female>74%.This method combined with MCV and MCH can significantly improve the sensitivity and negative expected value of thalassemia screening.This method was also helpful to screen out the carriers of thalassemia from blood donors in areas with high incidence of thalassemia,and provides support for further ensuring the safety of blood transfusion and realizing accurate blood transfusion.