ABSTRACT
OBJECTIVE: To assess the validity of SARS-CoV-2 Antigen (Ag) detection for the diagnosis of SARS-CoV-2 infection in mildly infected or asymptomatic patients. METHODS: Observational study to evaluate diagnostic tests. Non-hospitalized patients with indication for diagnostic testing for SARS-CoV-2 infection were included. The diagnostic test to be evaluated was the determination of Ag and as a reference standard to determine the presence of viral RNA the RT-PCR was used. RESULTS: A total of 494 patients were included. Of these 71.5% (353/494) had symptoms and 28.5% (141/494) were asymptomatic (presurgery screening (35/494) and confirmed case-contact (106/494). The overall sensitivity of the Ag test was 61.1% and the specificity was 99.7%. The sensitivity and specificity in the asymptomatic group were 40% and 100% respectively, and in the symptomatic group 63.5% and 99.6% respectively. In turn, the sensitivity and specificity in the group of symptomatic patients varied according to the time of symptom evolution: in patients with recent symptoms, they were 71.4% and 99.6% respectively, while in patients with symptoms of more than 5 days of evolution, they were 26.7% and 100% respectively. In all groups studied, the presence of antigen is associated with a high viral load (Ct<30 cycles). CONCLUSIONS: The use of Ag detection test is not indicated for the diagnosis of SARS-CoV-2 infection in asymptomatic patients or with symptoms of more than 5 days of evolution, but it could be useful in patients with symptoms of 1-5 days of evolution.
Subject(s)
COVID-19 , SARS-CoV-2 , False Positive Reactions , Humans , Reference Standards , Sensitivity and SpecificityABSTRACT
Objetivo: Describir un brote nosocomial de gripe A. Material y métodos: Se describe el Servicio de Medicina Digestiva donde aparecieron los casos. A los pacientes ingresados (n=47), entre el 17 de febrero y el 10 de marzo de 2012, se les realizó una encuesta epidemiológica, y a partir de esta, se describen sus características clínico-epidemiológicas (motivo de ingreso, días de hospitalización hasta el inicio de los síntomas, etc.) de los casos de gripe. Se evaluó la cobertura vacunal y la presencia de sintomatología respiratoria entre el personal sanitario (n=44), y se describen las medidas de control de infecciones puestas en marcha. Resultados: Hubo 10 pacientes con sospecha de gripe (seis de ellos confirmados) y 12 profesionales sanitarios con sospecha (dos confirmados). La cobertura vacunal en el personal sanitario de la unidad era del 18,2% (8/44). Conclusión: Se ha producido una asociación temporo-espacial de casos de gripe de adquisición nosocomial, donde la baja cobertura de la vacunación antigripal y la escasa adherencia a las Precauciones Estándar por parte del personal sanitario han podido ser factores determinantes para su aparición
Objective: Describe a nosocomial flu outbreak. Material and methods: The Service of Digestive Medicine where cases appeared is here described. Patients admitted (n=47) between February 17 and March 10, 2012 an epidemiological survey was does to each of them, obtaining their clinical and epidemiological characteristics (entry reason number of hospitalization days until the beginning of the symptoms, etc.) of the influenza cases. The vacunal coverage and the presence of respiratory symptoms in the health personnel were evaluated (n- 44). Moreover, the descriptions of all the infectious diseases control measures that were initiated are also described. Results: There were 10 patients (six of them confirmed) and 12 health professionals (two of them confirmed) with flu suspicion. The vaccination coverage in the health care workers of the unit was 18, 2% (8/44). Conclusions: An association was established between those cases of nosocomial influenza and the low influenza vaccination coverage of healthcare workers, which also had poor adherence to Standard Precautions. This may have been decisive risk factors for the emergence of this nosocomial outbreak of influenza
