[Indirect immunofluorescence technique versus polymerase chain reaction for the diagnosis of respiratory viruses in children admitted to a hospital in the Metropolitan Region]. / Inmunofluorescencia indirecta versus reacción de polimerasa en cadena para el diagnóstico de virus respiratorios en niños ingresados en un hospital de la Región Metropolitana.

BACKGROUND: Early viral detection in acute respiratory infections (ARI) is essential to establish appropriate therapy and prevent nosocomial transmission. OBJECTIVE: To compare the efficacy of indirect immunofluorescence technique (IIF) with the polymerase chain reaction (PCR) to identify respiratory viruses in children hospitalized for ARI. METHODS: 47 nasopharyngeal aspirates of children ≤ 2 years with ARI were included. IFI included respiratory syncytial virus (RSV), adenovirus, influenza A and B and parainfluenza. PCR also included the detection of metapneumovirus, enterovirus/rhinovirus, bocavirus and coronavirus. Sensitivity, specificity, positive and negative predictive value (VPP/NPV) and kappa correlation for RSV were estimated by IIF compared to PCR. RESULTS: The IIF detected only RSV (29; 61.7%). PCR detected several viruses, including RSV in 26 cases (55.3%), followed by bocavirus (29.8%), rhinovirus/enterovirus (21.3%), adenovirus (14.9%) and parainfluenza (4,3%) among others, with 35.5% of coinfection. The IIF presented sensitivity: 85.7%, specificity: 73.6%, PPV: 82.7%, NPV: 77.7% and kappa: 0.5990 (95% CI, 0.3636-0.8346) for RSV. CONCLUSION: The IIF presents good sensitivity, but moderate specificity for RSV. However, IIF fails to detect other respiratory viruses. The introduction of PCR would improve the etiological diagnosis of ARI of viral origin.

Inmunofluorescencia indirecta versus reacción de polimerasa en cadena para el diagnóstico de virus respiratorios en niños ingresados en un hospital de la Región Metropolitana / Indirect immunofluorescence technique versus polymerase chain reaction for the diagnosis of respiratory viruses in children admitted to a hospital in the Metropolitan Region

Resumen Introducción: La temprana detección viral en infecciones respiratorias agudas (IRA) es esencial para establecer una terapia apropiada y prevenir el contagio intrahospitalario. Objetivo: Comparar la eficacia de la técnica de inmunofluorescencia indirecta (IFI) con la reacción de polimerasa en cadena (RPC) para identificar virus respiratorios en niños hospitalizados por IRA. Métodos: Se incluyeron 47 aspirados nasofaríngeos de niños ≤ 2 años con IRA. La IFI incluyó virus respiratorio sincicial (VRS), adenovirus, influenza A y B y parainfluenza. La RPC incluyó, además, la detección de metapneumovirus, enterovirus/rinovirus, bocavirus y coronavirus. Se estimó sensibilidad, especificidad, valor predictor positivo y negativo (VPP/VPN) y correlación kappa para VRS mediante IFI en comparación a la RPC. Resultados: La IFI detectó únicamente VRS (29; 61,7%). La RPC detectó diversos virus, entre ellos VRS en 26 casos (55,3%), seguido por bocavirus (29,8%), enterovirus/ rinovirus (21,3%), adenovirus (14,9%) y parainfluenza (4,3%) entre otros, con 35,5% de co-infección. La IFI presentó sensibilidad: 85,7%, especificidad: 73,6%, VPP: 82,7%, VPN: 77,7% y kappa: 0,5990 (IC 95%; 0,36360,8346) para VRS. Conclusión: La IFI presenta buena sensibilidad, pero moderada especificidad para VRS. Sin embargo, falla en la detección de otros virus respiratorios. La introducción de RPC permitiría mejorar el diagnóstico etiológico de las IRA de origen viral.

Background: Early viral detection in acute respiratory infections (ARI) is essential to establish appropriate therapy and prevent nosocomial transmission. Objective: To compare the efficacy of indirect immunofluorescence technique (IIF) with the polymerase chain reaction (PCR) to identify respiratory viruses in children hospitalized for ARI. Methods: 47 nasopharyngeal aspirates of children ≤ 2 years with ARI were included. IFI included respiratory syncytial virus (RSV), adenovirus, influenza A and B and parainfluenza. PCR also included the detection of metapneumovirus, enterovirus/rhinovirus, bocavirus and coronavirus. Sensitivity, specificity, positive and negative predictive value (VPP/NPV) and kappa correlation for RSV were estimated by IIF compared to PCR. Results: The IIF detected only RSV (29; 61.7%). PCR detected several viruses, including RSV in 26 cases (55.3%), followed by bocavirus (29.8%), rhinovirus/enterovirus (21.3%), adenovirus (14.9%) and parainfluenza (4,3%) among others, with 35.5% of coinfection. The IIF presented sensitivity: 85.7%, specificity: 73.6%, PPV: 82.7%, NPV: 77.7% and kappa: 0.5990 (95% CI, 0.3636-0.8346) for RSV. Conclusion: The IIF presents good sensitivity, but moderate specificity for RSV. However, IIF fails to detect other respiratory viruses. The introduction of PCR would improve the etiological diagnosis of ARI of viral origin.