Determination and application of the cutoff value of mean corpuscular volume in thalassemia minor and silent gene carrier

Objective To investigate the cutoff value of mean corpuscular volume in thalassemia minor and silent gene carrier and its application.Methods Produce aged couples in Nanning countryside were screened for thalassemia.One hundred and fifty-three cases were established as control healthy by gene analyze and serum ferritin measurement.Fifty-five cases were diagnosed β-thalassemia heterozygote,76 cases of α-thalassemia 1,59 cases of α-thalassemia 2,18 cases of αβ-thalassemia combination with slight anemia or without anemia.mean corpuscular volume(MCV) were measured by Cell Dyn 1700 hematology cytoanalyze.Cutoff value is determined by receptor operate curve(ROC),then Its application in clinic diagnose is analyzed.Results The cutoff value for diagnosing minor or silent thalassemia is ≤78.25 fl(sensitivity:85.6%,specificity:94.8%).According to the cutoff value,8 cases of false positive are found in 153 healthy controls,28 cases of false negative are found in 59 cases of α thalassemia-2,no false negative is found in 55 cases of β thalassemia heterozygote,76 cases of α thalassemia-1 and 18 cases of αβ-thalassemia combination.Conclusion Cutoff value(≤78.25fl) of MCV for screening β-thalassemia and αthalassemia-1 is of rather applicable.