359. Clinical implications of SARS-CoV-2 PCR presumptive positive results

Abstract Background Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) reverse transcriptase (RT) polymerase chain reaction (PCR) testing is a cornerstone of coronavirus disease 2019 (COVID-19) diagnostics. A number of RT-PCR tests are currently available with different combinations of target genes including the pan-Sarbecovirus E gene target. When the E gene target is positive and the SARS-CoV-2 specific target is negative, the result is reported as presumptive positive which may indicate 1) a sample at concentrations near or below the limit of detection, 2) a mutation in the SARS-CoV-2 specific target, 3) infection with some other Sarbecovirus or 4) other factors. However, what the presumptive positive results mean clinically and whether they should be treated in the same way as the positive results are unknown. Methods We conducted a retrospective review of electronic health records for patients who had the presumptive positive results by Xpert Xpress SARS-CoV-2 (Cepheid, Sunnyvale, CA) or Cobas SARS-CoV-2 (Roche Molecular Systems, Branchburg, NJ) at Truman Medical Center from April 13, 2020 to December 31, 2021. Demographics, comorbidities, symptoms, laboratory data, radiographic data, clinical course and COVID-19 related complications were recorded and analyzed. Results During the study period, 85,267 SARS-CoV-2 RT-PCR tests were performed and 253 (0.3%) presumptive positive results were reported for 243 patients. Symptom information were available for 178 patients and 70% of them were symptomatic at the time of testing. Only 2 patients were admitted for COVID-19 pneumonia with the presumptive positive results. Both of them had low oxygen requirement during hospitalization and were discharged with stable conditions. Conclusion Symptomatic COVID-19 patients who presented with presumptive positive results by Xpert Xpress SARS-CoV-2 or Cobas SARS-CoV-2 had generally mild disease and rarely required hospitalization for COVID-19. Disclosures All Authors: No reported disclosures


Session: P-15. COVID-19 Diagnostics
Background. One of the tests used to identify COVID-19 infections is the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) reverse transcriptase quantitative polymerase chain reaction (RT-qPCR) test. There is a measure known as the cycle threshold (Ct) value, which provides an indirect measure of viral load. It has been proposed that the Ct value could help with clinical decisions regarding duration of isolation. We hypothesize that Ct values will correlate with symptom duration in a population of veterans with COVID-19 infection.
Methods. We reviewed the records of patients presenting to the emergency department (ED) or admitted to Audie L. Murphy VA Medical Center in San Antonio, Texas with positive SARS-CoV-2 PCR tests. We looked at patients who received multiple SARS-CoV-2 RT-qPCR tests. We compared date of onset of symptoms and cycle threshold values from their initial test to another test ordered after 7, 10, and 20 days from symptom onset. We recorded the Ct value for the N2 and E genes. Patients were classified into mild, severe and critical based on Center for Disease Control and Prevention (CDC) criteria. A Ct value of >30 as threshold for transmissible disease was used based on previously published studies.
Results. We identified 49 patients with more than two SARS-CoV-2 RT-qPCR tests. Patients with mild disease with tests less than or equal to ten days from symptom onset (n=10) had a mean Ct value 23.2 (±5.6) and 26.0 (±5.8) for the E and N2 genes. Patients with mild disease with tests greater than ten days from symptom onset (n=4) had mean Ct values of 26.0 (±6.5) and 27.8 (±6.8). When we stratified the patient population by disease severity, patients with severe and critical disease with tests less than ten days from symptom onset (n=24) had mean Ct values of 20.1 (±7.3) and 23.4 (±7.5). Patients with severe and critical disease greater than twenty days (n=6) had Ct values of 29.0 (±5.1) and 31.1 (±5.4).
Conclusion. We found that Ct values increased with longer symptom duration. We currently use the CDC criteria to discontinue isolation at ten days for mild disease and twenty days for severe and critical disease. The findings of this study suggest that our current practice for duration of isolation correlates with increasing Ct values near or above the threshold for transmissible disease.
Disclosures. All Authors: No reported disclosures Background. Novel SARS CoV2 may target the central nervous system and several neurological symptoms have been reported in patients with Coronavirus disease . Mucocutaneous and inflammatory symptoms are important in pediatric population associated to immune dysregulation. There are few reports of clinical manifestations in children and less frequently the isolation and affection of Central Nervous System.

Aseptic Meningitis Associated to SARS Cov2 Infection and MIS-C: Pediatric Presentation of Covid-19
Methods. A previously healthy four months female infant with familiar contact to SARS-CoV2 four weeks ago. Start with fever of 104°F, vomiting, maculopapular rash on the anterior thorax and upper extremities involving the palms and soles associated with edema. On physical examination, irritable, bulging anterior fontanelle, non-purulent bilateral conjunctival injection, cheilitis and rash was confirmed.
Results. Laboratory findings: thrombocytopenia, elevated D-Dimer, fibrinogen, PCT, CRP, ferritin and ESR with hypoalbuminemia. MIS-C is integrated with cutaneous, gastrointestinal and neurological affections. Empirically ceftriaxone, vancomycin and acyclovir are started due to suspicion of meningoencephalitis. RT-PCR