CC BY-NC-ND 4.0 · J Lab Physicians 2023; 15(03): 437-442
DOI: 10.1055/s-0043-1764481
Original Article

Traversing Their Path to the Peripheral Smear: The Journey of Traumatized Red Blood Cells

Chethana Mannem
1   Department of Pathology, Kempegowda Institute of Medical Sciences (Affiliated to Rajiv Gandhi University of Health Sciences), Bangalore, Karnataka, India
Tuba Saher
1   Department of Pathology, Kempegowda Institute of Medical Sciences (Affiliated to Rajiv Gandhi University of Health Sciences), Bangalore, Karnataka, India
Gayathri Bilagali Ramdas
1   Department of Pathology, Kempegowda Institute of Medical Sciences (Affiliated to Rajiv Gandhi University of Health Sciences), Bangalore, Karnataka, India
› Author Affiliations
Funding Nil.


Background 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.

Objectives 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.

Materials and Methods 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.

Results 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 (p < 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.

Conclusion 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.

Ethical Approval

Ethical clearance was obtained from the Institutional Ethics Committee, Kempegowda Institute of Medical Sciences, dated 10/7/2021, bearing the reference number KIMS/IEC/A049/M/2021.

Details of Earlier Presentation

Presented as online oral paper in Karnataka Chapter-Indian Association of Pathologists and Microbiologists—KCIAPM—annual state conference held in September 2021.

Authors' Contributions

T.S. helped in conception and design of the study, acquisition of data, interpretation of data, and drafting of the article. C.M. was involved in conception and design of the study, analysis and interpretation of data, critical revision of the draft, and final approval of the version. G.B.R. helped in conception and design of the study, analysis and interpretation of data, critical revision of the draft, and final approval of the version.

Publication History

Received: 26 July 2022

Accepted: 28 December 2022

Article published online:
27 March 2023

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