血液分析仪白细胞分类报警阈值的ROC曲线分析

目的应用受试者工作特征(ROC)曲线对CELL-DYN 3700血液分析仪白细胞分类结果进行分析,建立本室最佳报警参考阈值。方法将238例患者静脉血标本以EDTA-K2抗凝,分别用仪器和显微镜进行白细胞分类,以SPSS 10.5统计软件的ROC曲线对5种分类参数不同阈值进行分析,选择曲线下面积(AUC)最大者为本实验室报警阈值,并与仪器设置阈值进行比较。结果经ROC曲线分析,仪器设置各参数阈值分别为中性粒细胞(N)<50%或>75%、淋巴细胞(L)<20%或>40%、单核细胞(M)>12%、嗜酸性粒细胞(E)>5%、嗜碱性粒细胞(B)>2%诊断试验整体准确性中等(AUC=0.792);当N>80%或N<20%、L>50%或L<10%、M>10%、E>5%、B>1.5%时AUC最大(AUC=0.926),诊断试验整体准确性优秀。最佳报警阈值对显微镜分类正常或异常标本判别的敏感度、特异度和准确度分别为0.91、0.90和0.91,明显优于仪器设置阈值。结论实验室应建立自己的报警阈值,以提高显微镜协同工作的有效性。

Analysis of blood cells differential alarm threshold values of the blood analyzer with receiver operating characteristic curve

Objective To evaluate the white blood cell differential results of the blood analyzer CELL-DYN 3700 by receiver operating characteristic(ROC) curve and establish the best alarm threshold value of our laboratory. Methods 238 venous blood samples treated with dipotassium ethylenediamine tetraacetic acid(EDTA-K_2) were collected.The white blood cell differential counts of each sample was performed with both the instrument and microscopy.ROC curve was used to evaluate the threshold values of the five white blood cell differential parameters.The the biggest differential threshold value of the area under the curve(AUC) was chosen as the laboratory's differential alarm threshold value and was compared with the threshold set by the instrument. Results As was analyzed by ROC curve,the threshold values of the parameters set by the instrument were neutrophil(N)<50% or >75%,lymphocyte(L)<20% or>40%,monocyte(M)>12%,eosinophil(E)>5%,basophil(B)>2% and with these values the general accuracy of diagnosis was moderate.When the threshold values were set as N>80% or N<20%,L>50% or L<10%,M>10%,E>5%,B>1.5%,AUC was the biggest(AUC=0.926) and the general accuracy of diagnosis was optimal.The sensitivity,specificity and accuracy of the optimal alarm threshold values were 0.91,0.90 and 0.91 in judgment of the normal and the abnormal samples. Conclusions Setting up appropriate alarm threshold values in the laboratory can improve cooperation efficiency of instrumental and microscopical determination.