Thrombogram: case report of pseudothrombocytopenia

ABSTRACT The thrombogram is one of the components of the blood count that includes platelet quantification and evaluation. The presence of laboratory artifacts, such as incorrect platelet counts by autoanalyzers, can lead to pseudothrombocytopenia, which is responsible for 15% to 30% of the cases of isolated thrombocytopenia observed in laboratory routine. Pseudothrombocytopenia induced by the anticoagulant ethylenediaminetetraacetic acid (EDTA) is one of the most frequent cases in which the presence of anticoagulant in blood samples can cause platelet aggregation or platelet satellitism. Careful observation of the data emitted by autoanalyzers, such as platelet and flag histograms, is crucial. Other procedures, such as checking for clotting in the sample, repeating the sample and viewing a peripheral blood smear, requesting a new sample taken with another type of anticoagulant, such as citrate, are imperative for the confirmation of cases of pseudothrombocytopenia.摘要 血小板检测图谱（thrombogram）是血液细胞计数项目的组成部分之一，涵盖血小板定量检测与质量评估。实验室检验伪迹（如自动分析仪给出的异常血小板计数结果）可引发假性血小板减少症，该病症占临床实验室日常检测中孤立性血小板减少症病例的15%至30%。由抗凝剂乙二胺四乙酸（ethylenediaminetetraacetic acid, EDTA）诱导的假性血小板减少症是最为常见的病例类型之一，此类病例中血液样本内的抗凝剂会引发血小板聚集或血小板卫星现象。仔细观察自动分析仪输出的相关数据（如血小板直方图与警示标志直方图）至关重要。其余用于确诊假性血小板减少症的必要操作包括：检查样本是否存在凝血、复检样本并镜检外周血涂片，以及申请使用另一类抗凝剂（如枸橼酸钠）重新采集样本。