Hematological parameters in covid-19 illness: Emphasis on platelet indices as a marker of severity of disease

ABSTRACT

Aims&Objectives: To study the hematological parameters and platele tindices and correlate with the severity of disease in COVID-19 positive patients. Patients/Materials & Methods: A record based study conducted in a tertiary care centre included 125 COVID-19 positive patients diagnosed by either RT-PCR orrapidantigentest. The clinical data was retrieved from the case records and the cases were categorized as mild, moderate, severe and critical based on the consensus guidelines. Hematological parameters studied were hemoglobin, RBC indices, total leucocyte count, neutrophil lymphocyte ratio (NLR), platelet count, platelet indices (plateletcrit, platelet distribution width, mean platelet volume and platelet large cell ratio) and D-dimer. Each of the parameters were correlated with these verity of the disease and statistical analysis was done using IBMSPSS software. Results: The mean age was 53.3 years (range 3-96 years) with male preponderance observed in 62.3% of cases. of the 125 cases, 57 patients were categorized as mild disease, 42 moderate, 16 severe and 10 with critical illness. Cases with severe and critical COVID-19 illness were associated with eosinopenia and neutrophillymphocyte ratio more than 3.3 (p value of both<0.05). Platelet count was normal in 69% cases. of the 39 patients with thrombocytopenia, as many as 59% had mild reduction (1.0-1.5 lakh/cumm). Among the various platelet parameters plateletcrit (PCT) was significantly lower in mild COVID illness in comparision with moderate to critical disease (p<0.05) while mean platelet volume and platelet distribution width was higher in severe and critical COVID illness (p value<0.05). PLCR did not show any statistical significance. Elevation of d-dimerlevels positively correlated with the severity of the disease. Patients with mild COVID-19 illness had mean D-dimer level of 0.86 Âμg/dl while patients with critical illness had 4.01 Âμg/ dl. Discussion & Conclusion: In addition to the known hematologic paratmeters implicated in COVID-19 illness such as NLR, eosinopenia and D-dimer, platelet parameters (MPV, PDW and PCT) can also be used as biomarkers that indicate the severity of the disease.