Serum calprotectin as a novel biomarker for severity of COVID-19 disease.

Background Some biomarkers have been reported to be related to the prognosis of the coronavirus disease 2019 (COVID-19). There are sparse data regarding the prognostic value of serum calprotectin in COVID-19 patients. Aims This study aimed to investigate the relationship between serum calprotectin level and clinical severity of COVID-19 disease in hospitalized patients. Methods This retrospective cross-sectional cohort study included 80 consecutive hospitalized patients with confirmed diagnosis of COVID-19. The study population was divided into two groups as patients hospitalized in the intensive care unit (ICU) and patients hospitalized but not in the ICU. The serum calprotectin levels, other laboratory, and clinical parameters were compared between groups. Results The mean age of the patients was 66.5 ± 15.7 years. Of the patients, 42 were in the ICU and 38 were not. Serum calprotectin level and acute-phase reactants such as C-reactive protein, procalcitonin, ferritin, fibrinogen, and white blood cell were significantly higher in ICU patients than in non-ICU patients. ROC curve analysis identified that serum calprotectin level was a predictor for ICU requirement with an area under the curve of 0.641 (p = 0.031). Logistic regression analysis revealed that serum calprotectin was a significant determinant for whether or not patient required the ICU. Conclusions These findings demonstrate that serum calprotectin level seems to be a useful biomarker that can predict the severity of COVID-19 disease. Serum calprotectin is a significant predictor of ICU requirement in patients with COVID-19.