应用ROC分析法探讨新生儿筛查PKU切值

目的:应用ROC分析法对用荧光分析法检测新生儿足跟血苯丙氨酸(Phe)含量筛查苯丙酮尿症(PKU)的切值(cut-off)进行探讨和确定。方法:采集深圳市各设产科医院出生72h后并充分哺乳的新生儿足跟血滴加在S&S903#滤纸上制成滤纸干血斑标本,采用荧光分析法进行检测,统计分析227426例新生儿Phe水平分布,用ROC分析法对204例筛查阳性新生儿进行灵敏度及误诊率等分析。结果:9例患儿中最高值为11.95mg/dl,最低值为2.35mg/dl,ROC分析界值下的面积为0.891,结果显示当界值取2.0mg/dl时其敏感度为100%、特异度为20.5%,而当取2.32mg/dl时其敏感度仍为100%、特异度为45.6%,特异度可提高25.1%。结论:用荧光分析法检测Phe筛查PKU可以将切值确定为2.3mg/dl。

Exploration on cut off value of PKU screening in neonates by ROC analysis

Objective: To explore and define the cut off value of phenylketonuria ( PKU) screening by blood phenylalanine content detection with fluorescence analysis according to ROC analysis. Methods: The blood samples were collected from neonates within 72 hours after birth,then were detected by fluorescence analysis,the distribution of phenylalanine levels in 227 426 neonates was analyzed,ROC analysis was used to analyze sensitivity and misdiagnostic rate among 204 neonates with positive results. Results: Among 9 cases,the highest and lowest phenylalanine levels were 11. 95 mg/dl and 2. 35 mg/dl,respectively; the area under the ROC curve was 0. 891; when the critical value was 2. 0 mg/dl,the sensitivity and specificity were 100% and 20. 5% ,respectively; when the critical value was 2. 32 mg/dl,the sensitivity and specificity were 100% and 45. 6% ( increasing by 25. 1% ) ,respectively. Conclusion: The cut off value can be set at 2. 3 mg/dl in phenylalanine screening by fluorescence analysis.