Clinical application of commonly used screening methods for diagnosis of thalassemia

Objective To study the value of the red cell mean corpuscular volume(MCV),red blood cell (RBC)osmotic fragility test,hemoglobin(Hb) electrophoresis in the screening of thalassemia.Methods 200 samples of thalassemia and 80 samples of non-thalassemia verified by molecular biologic technique were detected by MCV test,RBC osmotic fragility test and Hb electrophoresis.To evaluate the sensitivity and specificity of different single test and combined detection.Results The sensitivity and specificity of single test were as follows:MCV 97.5% and 76.3% ,RBC osmotic fragility test:86.0% and 88.8%,Hb electrophoresis 82.0% and 93.8%.The sensitivity and specificity of combined MCV with RBC osmotic fragility test were 80.5% and 90.0%,RBC osmotic fragility test with Hb electrophoresis were 75.5% and 95.0%,MCV and RBC osmotic fragility test with Hb electrophoresis were 72.0% and 100%.Conclusion MCV test is more sensitive test in screening out thalassemia,MCV and RBC osmotic fragility test with Hb electrophoresis can greatly improve the specificity.However,these methods for α thalassemia,especially the light and static nature of α-thalassemia,have a high rate of missed diagnosis.