Diagnostic value of platelet indices in COVID 19 infection: a case-control study from a single tertiary care center

INTRODUCTION: Platelets are not only involved in hemostasis and coagulation, but play a significant role in innate immunity and inflammatory response. Excess production of cytokines and acute phase reactants affect megakaryopoiesis resulting in the release of immature platelets from the bone marrow altering platelet indices. AIM: To study platelet indices in RT-PCR-proven COVID patients and non-COVID patients. METHODS: A case-control study was conducted on 199 COVID-19 patients and 198 normal individuals. Blood samples were analyzed in an automated hematology analyzer. The platelet indices like platelet count, mean platelet volume (MPV), platelet distribution width (PDW), platelet large cell count (PLCC), and platelet large cell ratio (P-LCR) were compared among two groups. RESULTS: Platelet count in COVID-19 patients were significantly low (p<0.01) compared to controls, and a significant number of COVID-19 patients had thrombocytopenia. Plateletcrit (PCT) was also significantly decreased in COVID-19 patients compared to non-COVID individuals. MPV, PDW, and PLCR were significantly (p<0.05) high in COVID-19 patients in comparison to controls, but was not significantly raised in a large number of cases. In contrast, there were no significant differences in platelet large cell count (PLCC) values between COVID-19 cases and non-COVID-19 controls. CONCLUSION: Platelet indices like platelet count, PCT, MPV, PDW, and P-LCR are significantly altered in COVID-19 infection and thereby can be used as biomarkers in COVID-19. Further research is needed to find if these simple, cost-effective parameters can be used to predict the severity and prognosis in COVID-19 infection.