Plasma D-dimer : a promising indicator of COVID-19 infection severity or only an acute phase reactant.

Serum D-dimer levels, as well as other biomarkers related to coagulation, are significantly elevated during severe community acquired pneumonia. The aim of this study is to investigate the utility of plasma D-dimer levels determining the severity of inflammation and prognosis in pediatric patients with COVID-19 infection. We retrospectively chart reviewed medical records of pediatric patients (< 18 years of age) admitted to Istanbul Fcaulty of Medicine, Department of Pediatrics Infectious Disease Service between March 11, and June 30, 2020. We collected demographic, clinical, biochemical and radiographic data. A hundred and seventy-one pediatric patients (1 - 216 months of age) admitted to pediatric infecitous disease service included in this study. Patients were classified into 4 categories; 1) COVID-19 infection confirmed by PCR, 2) Suspected COVID-19 infection due to close exposure history and radiographic findings, 3) Lower respiratory tract infection other than COVID-19 confirmed with multiplex respiratory viral panel, and 4) Systemic infections other than lower respiratory tract infection. Lymphopenia was observed significantly higher in patients with COVID-19 infection compared to patients with other respiratory viral infections (p=0.06). In patients with radiographic findings concerning for COVID-19 infection, elevated serum D-dimer levels were detected significantly higher than lymphopenia (p=0.07). Elevated serum D-dimer levels at baseline are associated with inflammation especially in patients with COVID-19 infection with radipgraphic findings. Monitoring serum D-dimer levels may be used for early identification of severe cases in children.