BackgroundThe Beckman Coulter DxH 900 is a haematological analyser capable of counting and sizing blood cells, and obtaining a complete blood cell count (CBC). This analyses different parameters of red blood cells (RBC), platelets and white blood cells/leukocytes. Some automated CBC counters present limitations due to specimen characteristics, abnormal cells or both factors. In the presence of abnormalities, the DxH 900 has a flagging system, warning the laboratory technician that something needs to be verified. In the present work, we evaluated samples from oncologic patients, presenting a population erroneously perceived as being lymphocytes. The most common explanations for this situation are RBC resistant to lysis or serum hyperbilirubinaemia.MethodsIn an attempt to solve and understand what the cause of this problem might be, we diluted our samples (1:3) and analysed the serum total bilirubin. To identify cells' abnormalities, the samples were also analysed by manual DLC counts. During the study, we also checked the different flags presented by the equipment.ResultsThe results evidenced that the major interference was due to RBC lysis resistance, corresponding to 94.7% of the cases, while hyperbilirubinaemia was only present in 73.4%. Besides, we determined that some samples with normal bilirubin levels also presented interference, suggesting that hyperbilirubinaemia was not the main cause of the error. The most recurrent flag observed was “High event rate”.ConclusionThe dilution solved all of the observed interferences. The results between diluted and manual counts showed a strong correlation, leading us to introduce dilution in our laboratory routine.

中文翻译：

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稀释评估作为 Beckman Coulter DxH 900 中白细胞散点图干扰的校正措施

背景 Beckman Coulter DxH 900 是一款血液分析仪，能够对血细胞进行计数和大小测定，并获得全血细胞计数 (CBC)。这会分析红细胞 (RBC)、血小板和白细胞/白细胞的不同参数。由于样本特征、异常细胞或两者兼而有之，一些自动 CBC 计数器存在局限性。当出现异常情况时，DxH 900 具有一个标记系统，警告实验室技术人员需要验证某些内容。在目前的工作中，我们评估了肿瘤患者的样本，呈现出错误地认为是淋巴细胞的群体。这种情况最常见的解释是红细胞对溶解有抵抗力或血清高胆红素血症。方法为了解决和了解此问题的可能原因，我们稀释了样品（1:3）并分析了血清总胆红素。为了识别细胞异常，还通过手动 DLC 计数对样本进行了分析。在研究过程中，我们还检查了设备呈现的不同标志。 结果结果表明，主要干扰是由于红细胞溶解阻力造成的，对应于 94.7% 的病例，而高胆红素血症仅占 73.4% 的病例。此外，我们确定一些胆红素水平正常的样本也存在干扰，这表明高胆红素血症并不是造成错误的主要原因。观察到的最常见的标志是“高事件率”。结论稀释解决了所有观察到的干扰。稀释计数和手动计数之间的结果显示出很强的相关性，导致我们在实验室常规中引入稀释。