云南省德宏地区成人地中海贫血筛查中MCV和MCH截断值分析

Analysis of cut-off values of MCV and MCH for screening thalassemia in adults in Dehong,Yunnan

目的探讨云南省德宏地区成人地中海贫血(简称地贫)筛查指标平均红细胞体积(MCV)和平均红细胞血红蛋白含量(MCH)的最佳临界值。方法选取德宏傣族景颇族自治州人民医院9 562名行门诊检查、体检、婚检和遗传咨询的成年人,根据地贫常见基因突变检测结果将其分为地贫组(2 662例)和正常对照组(6 900名)。采用受试者工作特征(ROC)曲线分析MCV和MCH筛查地贫的最佳临界值及效能。结果 MCV筛查地贫的最佳临界值为83.95 fL,敏感性为82.7%,特异性为89.7%;MCH筛查地贫的最佳临界值为28.15 pg,敏感性为88.7%,特异性为89.2%。确定的临界值与目前国内广泛使用的临界值(MCV<80 fL和MCH<27 pg)相比,可显著降低漏诊率;联合使用MCV或MCH筛查地贫,漏诊率最低。结论适合的临界值可显著降低地贫漏诊率,建议具有独特突变谱的流行区建立自己的地贫筛查临界值,联合使用MCV和MCH进行筛查,以提高筛查效率。

Objective To investigate the optimal cut-off values of mean corpuscular volume(MCV) and mean corpuscular hemoglobin(MCH) for screening thalassemia in adults in Dehong,Yunnan. Methods Totally,9 562 adults undergoing outpatient examination,physical examination,premarital examination and genetic counseling in the People’s Hospital of Dehong Dai and Jingpo Autonomous Prefecture were enrolled,and they were classified into thalassemia group(2 662 cases) and healthy control group(6 900 cases) through the determination of common gene mutations of thalassemia. Receiver operating characteristic(ROC) curve was drawn based on the MCV and MCH results obtained from routine blood test in order to determine the optimal screening cut-off values and efficiencies. Results The optimal cut-off value of MCV was 83.95 fL,the screening sensitivity was 82.7%,and the specificity was 89.7%. The optimal cut-off value of MCH was 28.15 pg,the screening sensitivity was 88.7%,and the specificity was 89.2%. Compared with the cut-off values widely used in China(MCV<80 fL and MCH<27 pg),the screening cut-off values in this study may reduce the missed diagnosis rate,and the missed diagnosis rate of screening with MCV and MCH combinedly was the lowest. Conclusions Epidemic areas with unique mutation profiles may establish their screening cut-off values,and the combined screening of MCV or MCH may reduce the missed diagnosis rate and improve screening efficiency.