Comparison of platelet count by automated hematology analyzer and peripheral blood smear in thrombocytopenic patient

Platelet count estimation is one of the common as well as important laboratory investigations to diagnose many diseases like dengue, malaria etc. Different methods for platelet estimations are automated haematology analyzer, peripheral blood smear examination method etc. Most common causes of inaccurate platelet count by automated analyser are the presence of giant platelets, platelet clumps etc. leading to erroneous result like false low platelet count etc. We aimed to compare platelet count estimation by automated haematology analyzer and the peripheral blood smear examination in thrombocytopenic patients. A comparative cross-sectional study was conducted on 100 blood samples of patients which came thrombocytopenic on automated haematology analyzer. Each case was also analyzed by peripheral blood smear examination and compared with its corresponding automated haematology platelet count value. Our study included 63% males and 37% females, with the mean age of 38.8 years. Most of the patients belonged to the age group of 30-40 years (34%). The mean platelet count on automated analyzers was 85.46 ± 38.81 x 103/uL whereas on peripheral smear was 92.13 ± 38.30×103/uL with a significant difference between the two groups (p-value <0.0001).Pseudo-thrombocytopenia was observed in 10% of patients, with giant platelets observed in 29% of the cases on blood smear. In view of false low platelet count by automated analyser, we concluded that manual examination by peripheral blood smear examination should always be considered whose platelet count is low by automation.