17种免疫法粪便潜血试验检测性能评估

Performance evaluation of 17 fecal immunochemical tests

目的通过对17种常用免疫法粪便潜血试验(FIT)的检测性能进行评估,探讨结直肠癌筛查假阳性率较高的原因。方法以模拟粪便为样本,配制14个不同浓度的检测样本。采用17种FIT对模拟粪便样本进行检测,编号1～15为定性FIT,编号16～17为定量FIT。由7名操作人员进行检测,并记录结果。2种定量FIT由其中2名操作人员采用Luminex200多功能流式点阵仪与OC-Sensor全自动便潜血分析仪进行检测,并记录结果。结果共收集1 666份样本进行检测,11种定性FIT试剂阳性率高于理论阳性率(P<0.005),16、17号定量FIT试剂阳性率与理论阳性率差异无统计学意义(P16=0.43,P17=0.21),其粪便样本血红蛋白水平与理论浓度呈高度相关(r16=0.88,P<0.000 1;r17=0.92,P<0.000 1)。定性FIT的敏感性可达100.00%,且11种定性FIT的Kappa值均<0.40。16、17号定量FIT的敏感性均为86.21%,特异性分别为88.24%和97.06%,Kappa值分别为0.73、0.80。结论定性FIT成本低且操作方便,但缺乏对粪便取样量及稀释液的统一标准,实际阳性判断值低于预设阳性判断值,特异性低。定量FIT成本较高,但不易受人为主观判断影响,特异性相对较高。

Objective To investigate the reasons for high false positive rate of fecal immunochemical tests(FIT)through evaluating the performance of 17 common FIT.Methods Simulated feces samples with 14 different levels were prepared.Totally,7 laboratory assistants tested these samples by 15 qualitative FIT(No.1-No.15)and 2 quantitative FIT(No.16 and No.17).The results were recorded.A total of 2 automatic FIT analyzers,Luminex200 system and OC-Sensor,were used as well.Results A total of 1 666 samples were tested.The positive rate of 11 qualitative FIT was higher than theoretical positive rate(P<0.005).There was no statistical significance between the positive rate of 2 quantitative FIT and theoretical positive rate(P16=0.43,P17=0.21).There was a correlation between theoretical concentration and the hemoglobin levels tested by the 2 quantitative FIT(r16=0.88,P<0.000 1;r17=0.92,P<0.000 1).The sensitivities of qualitative FIT reached 100.00%,and the Kappa values of 11 qualitative FIT were <0.40.The sensitivities of 2 quantitative FIT(No.16 and No.17)were 86.21%,and the specificities were 88.24% and 97.06%,respectively,and the Kappa values were 0.73 and 0.80,respectively.Conclusions The qualitative FIT are cheap and convenient,but the quantity of feces samples and diluents are not standardized well,and the actual cut-off values are lower than given cut-off values,which can lead to the low specificity of qualitative FIT.The cost of quantitative FIT was high,they are not affected by subjective judgment,and the specificity is relatively high.