Diagnosing respiratory syncytial virus by nasal lavage.

Abstract

Nasal lavage was compared with nasopharyngeal aspiration for diagnosis of respiratory syncytial virus infection. Nasal lavage and nasopharyngeal aspiration were performed on 50 occasions in 32 infants (median age 5 6 months) with acute viral wheezing. Compared with nasopharyngeal aspiration, nasal lavage had a positive predictive value of 95-6% and negative predictive value of 92.5%. These comparable results and lack of adverse effects make nasal lavage the preferred method. (Arch Dis Child 1995; 72: 58- Subjects and methodsWe studied 32 infants who had been admitted to hospital with an acute episode of viral wheezing. Age range was 4 weeks to 2-6 years (median 5-6 months). The study was approved by the hospital ethics committee and parents gave verbal consent.Nasal lavage was performed followed by nasopharyngeal aspiration on 50 occasions; some of these were follow up samples when the children were symptom free. The subject was held in a supine position. Nasal lavage consisted of gently instilling 2 ml of phosphate buffered saline, at room temperature, into each nostril. This was simultaneously suctioned back using a soft rubber 8 or 10 FG Jaques catheter (TFX Medical) from the anterior nares. The catheter was attached to a standard mucus extractor (Universal Hospital Supplies) connected to wall suction. Nasopharyngeal aspiration was conducted using the standard technique. An 8 FG PVC catheter was pushed to the back of the nasopharynx and the aspirate collected into a mucus trap. Each procedure took only a few minutes and adverse effects were not encountered with either technique, although some samples from nasopharyngeal aspiration were mildly bloodstained.Nasal lavage fluid was centrifuged at 3000Xg for 20 minutes. The catheter used for nasopharyngeal aspiration was rinsed first with 1 ml viral transport medium before this mixture was centrifuged at 1500Xg for 10 minutes. The supematant was decanted and the pellet resuspended in sterile phosphate buffered saline. The washing procedure was repeated twice then the pellet was resuspended in 0-4 ml sterile phosphate buffered saline.The pellets contained intact epithelial cells; only 80% of cells obtained by lavage were intact compared with almost 1 00% from nasopharyngeal aspiration, but this was because the lavage samples had been frozen before analysis and would not be expected infresh samples. Direct immunofluorescence for RSV and influenza A antigens was carried out on the epithelial cells using commercial assays (Imagen, Dako Ltd) following the manufacturer's instructions. Influenza A was used as a control to detect non-specific fluorescence. ResultsSamples obtained by both techniques had a similar cellular composition, although nasal lavage gave a better cell yield.There were 24 RSV positive and 26 RSV negative samples from nasopharyngeal aspiration. Taking nasopharyngeal aspiration as gold standard, nasal lavage gave one false positive and two false negative results (table). This means nasal lavage has 96-2% specificity (with 95% confidence interv...

High Rates of Detection of Respiratory Viruses in the Nasal Washes and Mucosae of Patients with Chronic Rhinosinusitis

“…A major strength of this study was that the prevalence of respiratory virus was assessed using two sampling techniques: nasal lavage and mucosal scrapes from the inferior turbinate. Although respiratory samples for detection of respiratory viruses are generally collected by nasopharyngeal swabs or nasopharyngeal aspirate in adults (31), nasal lavage fluid and scraped inferior turbinate epithelial cells have been used to detect respiratory virus in upper respiratory tract (27,30,(32)(33)(34). This multitechnique approach to the detection of respiratory viruses improved the sensitivity, and the results of this study confirmed the prevalence of respiratory viruses in the nasal cavity of CRS patients.…”

BTS Guidelines for the Management of Community Acquired Pneumonia in Childhood

“…Nasal lavage can be substituted for nasopharyngeal aspirates. 59 The results of viral detection tests are particularly useful for cohorting infected children during outbreaks and for epidemiological purposes.…”

Comparison of three methods of collecting nasal specimens for respiratory virus analysis

“…Previous studies have demonstrated nasal washing to be operationally useful in the hospital(1,4) and community(5,6) settings, and have shown high viral titre yield(2,7). The procedure of nasal lavage, similar to NWs but with mechanical aspiration, has been shown to compare well with NPA in RSV diagnosis efficiency (8). Taken together with simpler equipment requirements, these facts suggest nasal washing methods may have considerable merit for use in minimal resource, and home, settings.…”