Pseudothrombocytopenia – frequency, causes, and evaluation in a clinical lab.

Objective: To find out frequency, different causes of pseudothrombocytopenia andtheir further evaluation to reach a final diagnosisMethodology: This cross-sectional study was conducted at Muhammad MedicalHospital, Mirpurkhas between October 2021 to January 2022. All patients who hadan automated platelet count less than 100 were included in the study. While patients with a known cause of thrombocytopenia were excluded. Data was collectedwith the help of designed proforma. Complete blood count was performed by anautomated hematology analyzer. The samples with platelet count less than 100(flag on platelet counts) were selected for peripheral blood smear review for manual counting to ascertain the cause of thrombocytopenia.Results: A total of 1800 blood samples were analyzed. 95 patients (5.27%) had isolated platelet count < 100 with no previous history. Peripheral blood smear reviewwas done, 84 patients (88%) had true thrombocytopenia that is low platelet countby both automated and manual techniques. The incidence rate of pseudothrombocytopenia was 0.61%. Clumping due to EDTA was found in 0.27% cases followed byplatelet satellitism in 0.05% cases.Conclusion: Our study reported an incidence of pseudothrombocytopenia to be0.61%. Further breakdown revealed clumping due to EDTA to be the most commoncause. Platelet Satellitism was found to be the cause of pseudothrombocytopenia in0.05% cases. Keywords: pseudothrombocytopenia, PTCP, spurious, thrombocytopenia.