Utility of Platelet Count and Platelet Indices in the Evaluation of Thrombocytopenia

Author(s): Tejaswi Peddaverannagari1 , Nalinimohan Chakkirala2 , Shailaja Prabhala3 , Ashokkumar Deshpande4

BACKGROUND Thrombocytopenia is defined as a low platelet count, less than 150000 / microlitre which is attributed to a variety of haematological and pathological disorders. It can result from four different mechanisms like hypoproduction, hyperdestruction, abnormal platelet distribution and dilutional loss. The type of mechanism leading to thrombocytopenia can be determined with the help of platelet count and platelet indices such as mean platelet volume (MPV), platelet distribution width (PDW) and plateletcrit (Pct). We wanted to study the utility of platelet count and platelet indices in the evaluation of thrombocytopenia, evaluate platelet indices as a diagnostic tool in differentiating various types of thrombocytopenia and correlate platelet indices with bone marrow findings. METHODS This was a prospective observational study done in a teaching medical college in India over a period of two years from June 2017 to May 2019. The patients were divided into two groups as hyperdestructive and hypoproductive related thrombocytopenia. The platelet count and platelet indices were determined in a five part haematology autoanalyzer and were compared with suitable controls. Findings were correlated with Bone marrow examination for exact aetiology. RESULTS A total of 60 patients was considered for the study, of which 21 belonged to hyperdestructive thrombocytopenia and 39 belonged to hypoproductive group. All 21 cases in the former group were of immune mediated thrombocytopenia (ITP). MPV 11.51 ± 1.97 was significantly higher in hyperdestructive thrombocytopenia as compared to hypoproductive thrombocytopenia wherein it was 8.34 ± 2. PDW was also more in the former group as compared to latter and showed a mean value of 16.67 ± 1.03 and 14.68 ± 2.29 respectively. The difference in Pct was insignificant in determining the cause of thrombocytopenia between the groups. CONCLUSIONS Platelet indices give valuable preliminary information as to the type of thrombocytopenia, i.e. hyperdestructive or hypoproductive type. This will guide in patient management decisions and may obviate the need for bone marrow examination in at least some patients. Also platelet indices do not need extra blood sample and do not incur additional cost.