新生儿脐血Hb Bart′s水平作为α-地中海贫血携带者早期筛查指标临床应用评价

Clincal application and evluation of Hb Bart's levels as an early screening index for alpha-tlalassemia carriers

目的 :将新生儿脐血HbBart’s水平作为α -地中海贫血携带者或患儿早期筛查指标进行临床应用评价。方法 :对 10 0 6份新生儿脐血标本同时采取琼脂糖碱性血红蛋白电泳和分子筛查技术分别进行HbBart’s定量和α -地中海贫血基因分析。结果 :在上述标本中 ,检出HbBart’阳性样品 64份 ,阳性率为 6.3 6%。此外 ,还检出异常Hb 6例 ,在这些阳性样品中 ,检出 2类 5种α -地中海贫血基因共 64份 ,其余的 90 6份阴性样品中尚检出α -地中海贫血基因阳性 3 8份 ,故该市户籍人群中总的α -地中海贫血基因携带率为 10 .44 %。HbBart’s水平筛查法对正常基因型和α -地中海贫血基因阳性样品的诊断符合率分别为99 .8%和 62 .1% ,假阳性率为 3 .1% ;而对静止型α -地中海贫血的漏检率高达 3 6.2 %。结论 :HbBart’s水平筛查法具有简便、快速且经济 ,并能对各型α -地中海贫血作出临床早期诊断 ,但对静止型α

Objective:To evaluate Hb Bart's levels in neonatal cord blood as an early clinical diagnostic method for alpha-thalassemia carrier detdction.Methods:A total of 1006 neonatal cord blood samples collected form shaoguan Maternal and Child Health Care Hospital were screened for α-thalassemia carriers with both Hb Bart's level and molecular screening method simultaneously. The sensitivity and specificity of Hb Bart's levels method were analyzed.Results:Hb Bart's was detected in 64 out of 1006 cord blood samples, the positive rate for Hb Bart's being 6.36%.Concentrations of Hb Bart's varied form 0.70% to 98.90%. Abnormal hemoglobin variants were also found in 6 samples(0.59%). In these positive samples for Hb Bart's, α-thalassemia mutations were detected in 64 samples, but α-thalassemia genes were detected in 38 out of 906 in the negative samples for Hb Bart's. Therefore, the incidence of α-thalassemia mutation was calculated as 10.44%. The overall diagnostic concordant rate of Hb Bart's screening method for α-thalassemia was 62.1%. When α-thalassemia with - SEA αα,-ααα,αααα T,- SEA -α and αααα genotypes, the dianostic concordant rate of the method was 100%, 19.1%, 100%, 100% and 99.8%,respectively. The false positive rate for α-thalassemia alleles was 3.1% and false negative rate for α-thalassemia with -ααα mutation was up to 36.2%.Conclusion: Hb Bart's level in the cord blood used as early clinical screening for various α-thalassemia is simpler and faster, more economic and easier to perform compared with the molecular screening method, but for silent α-thalassemia carriers. this method is unreliable and imprecise.