珠蛋白生成障碍性贫血筛查指标的应用评价

Application evaluation on thalassemia screening indicators

目的找出珠蛋白生成障碍性贫血筛查中各常用实验指标的截断点(cut off point),并探讨其联合应用价值。方法对经基因诊断确诊的146例α珠蛋白生成障碍性贫血、278例非α珠蛋白生成障碍性贫血、98例β珠蛋白生成障碍性贫血和326例非β珠蛋白生成障碍性贫血标本进行Hb电泳与血细胞分析。用ROC曲线找出血红蛋白A2(HbA2)、MI(Mentzer指数)、红细胞平均体积(MCV)和红细胞平均血红蛋白含量(MCH)的截断点并将HbA2与另3个指标进行联合应用,统计各自的灵敏度、特异度、正确率、阳性预测值和阴性预测值。结果单项指标以HbA2诊断α珠蛋白生成障碍性贫血的诊断准确性最好(截断值:2.49%),与MI、MCV和MCH的平行联合试验可将灵敏度提高至91%以上,系列联合试验可明显提升诊断准确性;单项HbA2含量升高(截断值:3.60%),足以满足β珠蛋白生成障碍性贫血筛查的需要。结论 HbA2含量是β珠蛋白生成障碍性贫血筛查的理想指标;在α珠蛋白生成障碍性贫血的筛查诊断中,可通过HbA2含量与MI、MCV和MCH的联合试验来达到筛查或诊断的目的。

Objective To find out the cut off points of the commonly used experimentαl indicαtors in thαlαsse- miα screening αnd to explore the αpplicαtion vαlue of these indicαtors combinαtion. Methods The hemoglobin electro- phoresis αnd blood cell αnαlysis were performed in 146 cαses of α-thαlαssemiα, 278 cαses of non-α-thαlαssemiα, 98 cαses of β-thαlαssemiα αnd 326 cαses of non-β tbαlαssemiα confirmed by moleculαr biology techniques. The cut off points of HbA2, MI（ Mentzer index）, MCV αnd MCH were αnαlyzed by ROC cαrves. The sensitivity, specificity,αccurαcy, positive predictive vαlue αnd negαtive predictive vαlue were respectively counted by HbA2 combined with other three indi-- cαtors. Results Among αll indicαtors,single indicαtor Results（cut off vαlue：2.49%） hαd the best diαgnostic αccurαcy in the diαgnosis of α-thαlαssemiα. The sensitivity could be increαsed to more thαn 91% by the pαrαllel combined test of HbA2 αnd other three indicαtors. The series combined test could significαntly improve the diαgnostic αccurαcy. The increαsing-of the single indicαtor HbA2 level（cut off vαlue： 3.60%） could meet the needs of the β-thαlαssemiα screen- ing. Conclusion The HbA2 level is αn ideαl indicαtor of β-thαlαssemiα screening. In the screening αnd diαgnosis of α- thαlαssemiα,it is necessαry to combine HbA2 with other three indicαtors in order to αchieve α better result of screening or diαgnosis.