The influence of COVID-19 on routine hematological parameters of hospitalized patients

Objectives Coronavirus disease 2019 (COVID-19) was first discovered in Wuhan, China, in December 2019, and soon spread around the entire world. As no effective treatment is known, prediction of disease severity is very important in order to estimate a patients outcome. Aim of this study was to evaluate routine hematology parameters in time after admission. Methods Data from routine blood analyses from confirmed COVID-19 cases admitted to the University Hospital of Leuven in Belgium were collected. COVID-19 patients (n = 197) were assigned to three groups: a 'non-ICU' group, a 'ICU' group and a 'deceased' group. A control group of 60 Influenza A (non-COVID-19) patients was also included. The parameters evaluated were platelet count (PLT, 10(9)/L), hemoglobin concentration (Hb, g/dL), leukocyte count (LEU, 10(9)/L), neutrophil count (NEU, %), eosinophil count (EO, %), lymphocyte count (LYM, %) and monocyte count (MONO, %). Results Deceased COVID-19 patients had significant lower platelet count, higher leukocyte/neutrophil count, and lower eosinophil/lymphocyte/monocyte count compared to recovered patients. Especially lymphocyte count showed important differences; they were significantly lower between day 9 and 12 after admission making this time window important in predicting clinical worsening of a patient. Conclusion Patients with COVID-19 with poor outcome showed significant differences in results of routine hematological parameters compared with patients that recovered. Especially lymphocyte count can be helpful in the prediction of a patients outcome.