Mentzer指数在鉴别轻型α地中海贫血与缺铁性贫血中的价值

摘要

Objective To evaluates the value of Mentzer index ( MI ) in differentiating alpha thalassemia carriers from iron deficiency anemia.Methods The data on alpha thalassemia gene,blood cell count,and serum levels of iron and ferritin were retrospectively analyzed in 151 patients with reduced hemoglobin A2( HbA2 )levels on hemoglobin electrophoresis.Based on α -globin gene analysis and levels of iron and ferritin,the patients were assigned to alpha thalassemia carriers group ( n =90 ),or iron deficiency anemia group ( n =61 ).Results MI differed significantly between iron deficiency anemia group and alpha thalassemia carriers with normal iron group ( P ＜ 0.01 ),iron deficiency anemia group and alpha thalassemia carriers with iron deficiency group ( P＜ 0.01 ),iron deficiency anemia group and alpha thalassemia carriers group ( P ＜ 0.01 ); but did not differ significantly between alpha thalassemia carriers with normal iron group and alpha thalassemia carriers with iron deficiency group ( P＞ 0.05 ).The area under the curve ( AUC ) for MI of receiver operating characteristic curve ( ROC ) was 0.849 between iron deficiency anemia group and alpha thalassemia carriers group,and the cut-off point was 13.1.As MI was -- 13.1,the sensitivity for detecting iron deficiency anemia was 96.7％,specificity 61.1％,and Youden index 0.58.If MI combined with RDW,the sensitivity was 100％.Conclusions Mentzer index has certain accuracy in differentiating alpha thalassemia carriers with reduced HbA2 levels from iron deficiency anemia.Both MI and RDW under the cut-off point can exclude the possibility of iron deficiency anemia.%目的 评估Mentzer指数(Mentzer index,MI)在鉴别HbA2减低中轻型α地中海贫血与缺铁性贫血中的价值.方法 回顾本院3年来血红蛋白电泳中HbA2减低的151例人群的α地贫基因、血常规、铁蛋白、血清铁数据,根据地贫基因分析和铁蛋白、血清铁水平将其分成2组:轻型α地中海贫血组(n=90),缺铁性贫血组(n=61).结果 缺铁组与地中海贫血无缺铁组、地中海贫血合并缺铁组、轻型α地中海贫血组三者比较中,MI有明显差异(P＜0.01),而在地中海贫血无缺铁组与地中海贫血合并缺铁组比较差异无显著性(P＞ 0.05).MI在缺铁组与轻型α地中海贫血组的ROC曲线下面积为0.849,并确定MI的截断点为13.1；以MI≥13.1时,缺铁性贫血检出的敏感度为96.7％,特异度为61.1％,尤登指数为0.58；若联合RDW、MI对两者进行鉴别,缺铁性贫血检出的敏感度为100％.结论 MI在鉴别HbA2减低中轻型α地中海贫血与缺铁性贫血有一定的准确性,MI与RDW两者均小于截断点可排除缺铁性贫血的可能.