Hoffmann J J M L, Hoedemakers R M J
Department of Clinical Laboratories, Catharina Hospital, Eindhoven, The Netherlands.
Clin Lab Haematol. 2004 Feb;26(1):9-13. doi: 10.1111/j.0141-9854.2003.00581.x.
In addition to differential cell counts, modern haematology analysers generate suspect flags if abnormal cells are detected. Reports on validation of suspect flags are scarce. We have routine experience with the Abbott Cell-Dyn 4000 analyser for over 5 years and have previously demonstrated the utility of the blast flag. Here we report a similar study on the performance of the analyser's Variant Lymphocyte (VL) flag.
Evaluation of the diagnostic performance of the Cell-Dyn 4000 VL flag, as compared with lymphocyte morphology in blood smears. In addition, we investigated the usefulness of the numerical VL flag confidence index as provided by the analyser.
All samples generating a VL flag were reviewed over a 5-month period. We also reviewed smears from patients with known lymphoid disorders, even if the analyser did not flag the sample. Two experienced investigators assessed lymphocyte morphology independently.
In total, 187 samples were included in the study, of which 183 had a VL flag and four had not. Of the 183 flagged samples, 83 appeared to have abnormal lymphocyte morphology and 100, normal lymphocyte morphology. The sensitivity of the VL flag for detecting abnormal lymphocytes was 0.95 and the positive predictive value was 0.44. Using ROC analysis of the VL flag confidence index, the area under the ROC curve was 0.58 (95% confidence interval 0.50-0.65).
The Cell-Dyn VL flag has reasonable sensitivity but a high false-positive rate. In addition, its performance is insufficient for detecting clinically relevant abnormal lymphocytes. As the VL flag appeared to rely mainly on numerical criteria, it has no added value over numerical criteria defined by the laboratory.
除了进行细胞分类计数外，现代血液学分析仪在检测到异常细胞时会生成可疑标记。关于可疑标记验证的报告很少。我们使用雅培Cell-Dyn 4000分析仪已有5年多的常规经验，并且之前已经证明了原始细胞标记的实用性。在此，我们报告一项关于该分析仪变异淋巴细胞（VL）标记性能的类似研究。
评估Cell-Dyn 4000 VL标记与血涂片淋巴细胞形态学相比的诊断性能。此外，我们还研究了分析仪提供的数值VL标记置信指数的有用性。
在5个月的时间内对所有生成VL标记的样本进行了复查。我们还复查了已知淋巴系统疾病患者的涂片，即使分析仪未对该样本进行标记。两名经验丰富的研究人员独立评估淋巴细胞形态。
该研究共纳入187个样本，其中183个有VL标记，4个没有。在183个有标记的样本中，83个似乎有异常淋巴细胞形态，100个有正常淋巴细胞形态。VL标记检测异常淋巴细胞的灵敏度为0.95，阳性预测值为0.44。使用VL标记置信指数的ROC分析，ROC曲线下面积为0.58（95%置信区间0.50 - 0.65）。
Cell-Dyn VL标记具有合理的灵敏度，但假阳性率较高。此外，其性能不足以检测临床相关的异常淋巴细胞。由于VL标记似乎主要依赖数值标准，因此它相对于实验室定义的数值标准没有附加价值。
