Mannem Chethana, Saher Tuba, Ramdas Gayathri Bilagali
Department of Pathology, Kempegowda Institute of Medical Sciences (Affiliated to Rajiv Gandhi University of Health Sciences), Bangalore, Karnataka, India.
J Lab Physicians. 2023 Mar 27;15(3):437-442. doi: 10.1055/s-0043-1764481. eCollection 2023 Sep.
Thrombotic microangiopathy encompasses a wide range of conditions, of which thrombotic thrombocytopenic purpura being a medical emergency requires prompt intervention, with schistocytes being a reliable morphological indicator of microvascular injury. However, there are conditions other than thrombotic microangiopathic anemia where schistocytes can be seen in large numbers. These nonthrombotic microangiopathic conditions are broadly grouped under cytoskeletal abnormalities, mechanical damage, and thermal injuries. Automated methods in schistocyte evaluation have shown varied reproducibility requiring manual identification. International Council for Standardization in Hematology (ICSH) recommends standardized morphological criteria and quantitative assessment as a percentage after counting at least 1,000 red blood cells in optimal areas of smear to reduce interobserver variability. The aim of this study was to evaluate and quantitate schistocytes in thrombotic microangiopathic and nonthrombotic microangiopathic groups using ICSH guidelines and to evaluate interobserver reproducibility of manual schistocyte count. Overall, 157 peripheral blood smears showing schistocytes were studied by two independent observers using ICSH recommendations on light microscopy. The hematological findings were correlated with clinical diagnosis and other relevant investigations. Schistocytes were observed in five cases of thrombotic microangiopathic anemia and 152 cases of nonthrombotic microangiopathic anemia. Schistocyte count in thrombotic microangiopathic anemia and nonthrombotic microangiopathic anemia groups with mean (±standard deviation) value was 2.28 ± 2.65% and 0.76 ± 0.67%, respectively ( < 0.001). The correlation coefficient between the two observers was 0.59 (confidence interval = 0.966-1.346) showing an excellent agreement on the reproducibility of schistocytes by application of ICSH guidelines. Percentage of schistocytes more than 1% is a robust morphological indicator for diagnosis of thrombotic microangiopathic anemia in adults. Strict application of ICSH guidelines reduces interobserver bias.
血栓性微血管病涵盖多种病症，其中血栓性血小板减少性紫癜作为一种医疗急症需要及时干预，裂红细胞是微血管损伤的可靠形态学指标。然而，除血栓性微血管病性贫血外，还有其他病症也可出现大量裂红细胞。这些非血栓性微血管病情况大致分为细胞骨架异常、机械损伤和热损伤。裂红细胞评估的自动化方法显示出不同的可重复性，需要进行人工识别。国际血液学标准化委员会（ICSH）建议采用标准化的形态学标准，并在涂片的最佳区域计数至少1000个红细胞后以百分比进行定量评估，以减少观察者间的差异。 本研究的目的是使用ICSH指南评估和定量血栓性微血管病组和非血栓性微血管病组中的裂红细胞，并评估人工裂红细胞计数的观察者间可重复性。 总体而言，两名独立观察者使用ICSH关于光学显微镜检查的建议，对157张显示裂红细胞的外周血涂片进行了研究。血液学检查结果与临床诊断及其他相关检查相关联。 在5例血栓性微血管病性贫血和152例非血栓性微血管病性贫血中观察到了裂红细胞。血栓性微血管病性贫血组和非血栓性微血管病性贫血组的裂红细胞计数平均值（±标准差）分别为2.28±2.65%和0.76±0.67%（<0.001）。两名观察者之间的相关系数为0.59（置信区间=0.966 - 1.346），表明应用ICSH指南对裂红细胞的可重复性具有良好的一致性。 裂红细胞百分比超过1%是诊断成人血栓性微血管病性贫血的有力形态学指标。严格应用ICSH指南可减少观察者间偏差。
