454. How Useful is SARS-CoV-2 Antigen Detection in Individuals Admitted to the Hospital With no Respiratory Symptoms?

BACKGROUND: Clinical findings and laboratory data have been crucial for timely diagnosis and transmission reduction of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) which causes Coronavirus disease (COVID-19). We have observed an increase in incongruent same day antigen and reverse transcription polymerase chain reaction (RT-PCR) results in all patients presenting to the hospital. This study aims to correlate SARS-CoV-2 test results with the presence of respiratory symptoms and to find the significance of performing the antigen screening test. METHODS: We conducted a single-center retrospective study, using electronic medical records of adults over 18 years of age who were tested routinely for COVID-19 with the Lyra SARS-CoV-2 RT-PCR Assay and the QuickVue SARS Antigen Test on presentation for any complaint from February 2022 to January 2023. We included all the patients who had a positive rapid antigen or RT-PCR test for COVID-19 admitted to the medical, or psychiatry unit. Patients admitted to the intensive care unit (ICU) or cardiac care unit (CCU) or those who returned a negative antigen and RT-PCR test were excluded from our study. We used the R software program to find the relative risk of pneumonia in these patients and performed pooled analysis with the random effects model. RESULTS: Overall, 178 adults were identified with at least one test positive and were divided into three groups. In patients with positive antigen and negative RT-PCR test 20.8% had respiratory symptoms while 79.1% did not. In patients with negative antigen and positive RT-PCR, 32% had respiratory symptoms and 68% did not. In the group that returned positive for both antigen and RT-PCR tests, only 40% had respiratory symptoms and 60 % did not. Fig. 1 demonstrates the relative risk (RR) of pneumonia (PNA) in all three groups which is less than 1. [Figure: see text] CONCLUSION: The relative risk of COVID-19 pneumonia is low in all three groups including those with a positive RT-PCR test, therefore COVID-19 antigen tests are not necessary until patients have severe respiratory symptoms or confirmed exposure. There is an ongoing need for clear guidelines for reliable detection of infection in hospitalized patients. DISCLOSURES: Jihad Slim, MD, FACP, ViiV Healthcare: Advisor/Consultant|ViiV Healthcare: Grant/Research Support