Ascertaining and Application of Cutoff Values of Mean Corpuscular Volume and Mean Hemoglobin Concentration in Positive Thalassemia Phenotype People

Objective To investigate the cutoff values of mean corpuscular volume (MCV) and mean hemoglobin concentration (MCH) for screening thalassemia and the value of their applications. Methods The husbands and wives with reproductive ages in the country of Nanning were screened for thalassemia. The Gene analysis showed that of 361 reproductive age young people with normal serum ferritin, 153 were healthful, 55 carried β thalassemia heterozygote, 76 suffered from thalassemia 1, 59 from thalassemia 2, and 18 from α and β compound thalassemia with mild or no anemia. Cutoff values of MCV and MCH for diagnosing thalassemia were ascertained by receiver operating curve (ROC) and their application were investigated. Results Cutoff value for diagnosing thalassemia is MCV≤78.25fl and MCH≤25.65pg, respectively. The sensibility and specificity of the ascertained cutoff value were 85.6% and 94.8% for MCV,82.7% and 94.8% for MCH, respectively. In 55 cases with β thalassemia heterozygote and 18 with compound thalassemia, MCV and MCH were lower than the above-mentioned cutoff value. In 76 case with α thalassemia 1, except 1 case with higher MCH than the cutoff value, MCV and MCH were also lower than the above-mentioned cutoff value. Of 59 cases with α thalassemia 2, 30 had higher MCV and 24 had lower MCH than the above-mentioned cutoff value. In the healthful adults, however, there were 8 cases with lower MCV and/or MCH than the cutoff value. Conclusion MCV≤78.25fl and MCH≤25.65pg used as the cutoff value for diagnosing thalassemia is rather reasonable.