确定血红蛋白A2筛查α地中海贫血临界值的方法探讨 [中文引用][英文引用]

目的 探讨实验室自己建立血红蛋白A₂筛查α地中海贫血临界值的方法。方法 分析本实验室近2年进行地贫筛查和地贫基因诊断的14 502例标本数据，将其分为α地贫组、非静止型α地贫组和正常对照组。以HbA₂不同的临界值分别计算筛查α地贫和非静止型α组地贫的敏感度、特异度、阴性似然比和阳性似然比，再分别绘制HbA₂筛查α地贫和非静止型α地贫的受试者工作曲线。结果 14 502例标本中2938例基因检测确诊为α地贫，其中静止型α地贫1129例，11 564例地贫基因检测为阴性；正常对照组的HbA₂结果为（2.62±0.28）%，α地贫组的HbA₂结果为（2.40±0.30）%，非静止型的α地贫组HbA₂结果为（2.30±0.26）%。得到了不同HbA₂临界值筛查α地贫和非静止型α地贫的性能，并获得了本实验室HbA₂筛查α地贫的最佳筛查临界值为＜2.7%。结论 HbA₂对非静止型α地贫有较好的筛查性能；各实验室应结合临床需求和自身实际情况建立自己的HbA₂筛查α地贫的临界值；本研究的思路和方法可供其他实验室借鉴，可降低α地贫的漏筛率。

Objective To study the method of determining the HbA₂ critical value of screening alpha thalassemia. Method To analyze our laboratory 14 502 samples data of thalassemia screening and genetic diagnosis in recent 2 years, which can be divided into alpha thalassemia group, non silent alpha thalassemia group and normal group. The sensitivity, specificity, negative likelihood ratio and positive likelihood ratio of screening alpha thalassemia and non silent alpha thalassemia based on different HbA₂ critical value were calculated. Then the ROC of screening alpha thalassemia and non silent alpha thalassemia by HbA₂ were drawn. Results 2938 samples were diagnosed as alpha thalassemia including 1129 silent alpha thalassemia, and 11564 samples were negative in 14 502 samples. The HbA₂ results of normal group were (2.62±0.28)%,the HbA₂ results of alpha thalassemia group were (2.40±0.30)%, and the HbA₂ results of non silent alpha thalassemia group were (2.30±0.26)%. The performance for screening alpha thalassemia and non silent alpha thalassemia based on different HbA₂ critical value were evaluated. The optimal critical value of screening alpha thalassemia by HbA₂ in our laboratory was determined ＜2.7%. Conclusions The performance for screening non silent alpha thalassemia by HbA₂ is better. Each laboratory should establish its own HbA₂ critical value of screening alpha thalassemia according to the clinical needs and the actual situation of their own. The ideas and methods of this research can be used for reference in other laboratories. And the missed rate of screening alpha thalassemia can be reduced.