Cadamuro Janne, Wiedemann Helmut, Felder Thomas K, Mrazek Cornelia, Kipman Ulrike, Hannes Oberkofler, Haschke-Becher Elisabeth
Department of Laboratory Medicine, Paracelsus Medical University, Salzburg, Austria.
UT SPSS Statistics, Hallein, Austria.
Biochem Med (Zagreb). 2017 Jun 15;27(2):430-433. doi: 10.11613/BM.2017.047.
We report on a preanalytical issue we encountered during routine clinical chemistry analyses, potentially leading to deviated analysis results and believe that it might help other laboratories to overcome similar problems. In a heparin-gel tube we measured an implausible glucose value of 0.06 mmol/L. Re-measurement of the same sample resulted in a glucose value of 5.4 mmol/L. After excluding an analytical error, we inspected the sample closer and found a white material as well as fatty droplets floating on the surface of the plasma tube. Evaluation of these structures revealed that the white particulate matter (WPM) consisted of fibrinogen, platelets and leukocytes and the fatty droplets most probably originated from the separator gel. We concluded that these structures formed a temporary clot in the instruments pipetting needle thereby altering the sampling volume and subsequently the measured glucose value. The formation of WPM might be attributable to high speed centrifugation, high cholesterol levels, the gel formulation or a combination of several issues such as temperature, heparin concentration, pH and patient-specific factors. The gel droplets were most probably caused by an aberrant gel formulation in combination with an improper storage of the empty tubes on the wards prior to phlebotomy. After adding an additional instrument cleansing cycle and changing to another batch of heparin tubes the problems could be significantly reduced.
我们报告了在常规临床化学分析过程中遇到的一个分析前问题，该问题可能导致分析结果偏差，并相信这可能有助于其他实验室克服类似问题。在一支肝素凝胶管中，我们测得的葡萄糖值为0.06 mmol/L，这一数值令人难以置信。对同一样本进行重新测量后，葡萄糖值为5.4 mmol/L。在排除分析误差后，我们对样本进行了更仔细的检查，发现血浆管表面漂浮着白色物质以及脂肪滴。对这些结构的评估显示，白色颗粒物（WPM）由纤维蛋白原、血小板和白细胞组成，而脂肪滴很可能源自分离胶。我们得出结论，这些结构在仪器的移液针中形成了一个临时凝块，从而改变了采样体积，进而影响了测得的葡萄糖值。WPM的形成可能归因于高速离心、高胆固醇水平、凝胶配方或温度、肝素浓度、pH值以及患者特定因素等多个问题的综合作用。凝胶滴很可能是由异常的凝胶配方以及在采血前病房中空管储存不当共同导致的。在增加一个仪器清洁周期并更换为另一批肝素管后，问题得到了显著减少。
