新生儿干血斑β地中海贫血筛查方法的研究

The study of beta-thalassemia screening methods of Neonate dry blood spot samples

目的探讨全自动毛细管微量血红蛋白电泳技术在新生儿β地中海贫血筛查中的应用价值,并寻求有效的筛查方法。方法使用Sebia全自动毛细管电泳仪对145904例新生儿滤纸干血斑标本进行血红蛋白(Hb)电泳;对95059例标本的电泳分析结果以HbA界值法判读β地贫筛查结果,对50845例标本的电泳分析结果以HbA值结合HbA2/HbA比值的综合分析法判读β地贫筛查结果,召回筛查阳性者进行地贫基因诊断;随机对600份标本的电泳结果同时以上述两种方法判读β地贫筛查结果,同时进行基因检测作为β地贫诊断的金标准,统计比较两种判读方法的差异。结果 HbA界值法筛查出的1580例阳性标本中经基因检测确诊为β地贫的有716例,确诊符合率45.32%,假阳性率为54.68%;综合分析法筛查出的1266例阳性标本中930例经基因检测确诊为β地贫,符合率73.46%,假阳性率为26.54%。同时对600例新生儿干血斑分析结果表明,HbA界值法和综合分析法的敏感度和特异度分别是54.55%、90.91%和97.58%、99.31%,两者的筛查准确性分别为96%和99%。统计结果表明,综合分析法的敏感度、阳性预测值和筛查的准确性显著高于HbA界值法.结论新生儿干血斑标本经毛细管血红蛋白电泳后,利用包含HbA、HbA2组分的含量及HbA2/HbA比值的综合分析法判读电泳结果,筛查新生儿β地贫,灵敏度和准确性显著提高,假阳性率明显降低,值得推广应用。

Objective Evaluate the application of capillary hemoglobin electrophoresis in neonate beta-thalassemia screening.Methods The Hb electrophoresis of 145904 dry neonatal blood samples was analyzed on Sebia Capillary Ne-onate Fast.The HbA cut-off value （Method I）was used to screen beta-thalassemia for 95059 dry blood samples and the combination of HbA value and HbA2/HbA ratio （Method II）was used to screen beta-thalassemia for the remaining 50845 dry blood samples.The subjects with positive results were recalled and confirmed by genotyping test.The 600 dry blood samples were collected randomly and the Hb electrophoresis results were check by both of Method I and Method II.The genotyping test was the reference to analyze the difference of both of the methods.Results The genetic diagnosis results of recalled 1580 positive cases according to the Method I showed that the true positive were 716 cases with true positive rate 45.32% and false positive rete 54.68%.The 930 cases were verified by genetic diagnosis among the recalled 1266 cases according to the Method II with true positive rate 73.46% and false positive rete 26.54%.The results of 600 samples showed that the sensitivity and specificity for beta-thalassemia screening of Method I and Meth-od II were 54.55%、90.91%和 97.58%、99.31% respectively.The true positive rates were 96% and 99% for Method I and Method II respectively.The results demonstrated that the Method II is superior to Method I for beta-thalassemia screening.Conclusion After the capillary dry blood Hb electrophoresis analysis,the combination of HbA value and HbA2/HbA ratio method for beta-beta-thalassemia screening is more sensitive and specific and lower false positive rate than HbA cut-off value method and the combination of HbA value and HbA2/HbA ratio method should be applied to more areas for newborn screening.