Assessment of pediatric patients with negative RT-PCR and CT-based COVID-19 diagnosis referred to ICU

Aim: Despite negative RT-PCR results, some pediatric patients show COVID-19 findings on thoracic CT imaging.This study aimed to evaluate laboratory parameters and clinical characteristics of RT-PCR-negative pediatric patients diagnosed with COVID-19 based on thoracic CT findings and referred to the intensive care unit.Materials and Methods: This retrospective study included 214 patients under 18 years presenting to the pediatric emergency department between March 15 and June 15, 2020.Patients with two negative RT-PCR tests but COVID-19 suspicion on thoracic CT requiring intensive care were enrolled.Patients were categorized into four age groups (0-2, 3-6, 7-11, 12-18 years) and classified as mild and severe hypoxemic patients.Laboratory parameters, including complete blood count, C-reactive protein, and D-dimer, were analyzed.Results: Mean ages were 1.30.5, 4.31, 9.41.4,and 14.61.6 years for respective age groups, with 57.9% males.Over half of patients in younger age groups were asymptomatic (57.1% in 0-2 years, 58.1% in 3-6 years).Significant differences were found between age groups in white blood cell count, lymphocyte, platelet, and red cell distribution width levels (p<0.05).The 0-2 age group showed higher lymphocyte (5.33.7) and platelet (387202) counts compared to older groups.D-dimer and mean platelet volume levels differed significantly between symptomatic and asymptomatic patients (p<0.05).A moderate negative correlation was found between clinical presentation and D-dimer levels (rs: -0.342, p<0.05).Discussion: Age-related variations in laboratory parameters suggest different immune responses across pediatric age groups in COVID-19.D-dimer and MPV may serve as potential biomarkers for disease severity assessment in RT-PCR-negative pediatric COVID-19 patients.