Diagnosis of SARS-CoV-2 by antigen test in a Pediatric Emergency Department

Abstract

Introduction. Finding an efficient and accessible diagnostic method for SARS-CoV-2 disease has been one of the big problems throughout the COVID 19 epidemic. Patients and methods. Retrospective descriptive study of the clinical data of patients undergoing antigen tests for SARS-CoV-2 carried out in the Pediatric Emergency Department of a tertiary hospital, between 22/12/2021 and 10/02/2022, and its concordance with the result of the RT-PCR of SARS-CoV-2 if available. Result. 653 antigen tests were performed (53.9% male), 26.6% were positive. The mean age was statistically higher in those with a positive result (67.3±51 months, compared to 51.95±51.3 months). The most frequent symptom among positive patients was fever in 79%. Among the 387 patients with a negative test, 92 RT-PCR were performed, resulting in positive 11 of them (12%) 9 of the 11 patients with positive RT-PCR had a close family contact and, of these, 7 had fever. The relationship between having a family contact and a positive antigen test (p<0.01) was significant, but not with another type of contact. Discussion. Patients who presented RT-PCR for SARSCoV-2 positive, with negative antigen test had mostly family contact and fever. Non-family contact had no higher percentage of false negatives than those with no known contact. The variation in positivity may be due to differences in the assessment of suspected case and sample collection technique.