Comparison of nasopharyngeal flocked swabs and aspirates for rapid diagnosis of respiratory viruses in children

• Published in: Journal of clinical virology Vol. 42; no. 1; pp. 65 - 69
• Main Authors: Chan, K.H, Peiris, J.S.M, Lim, W, Nicholls, J.M, Chiu, S.S
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01-05-2008; Elsevier Science
• Subjects: Adenovirus; Adolescent; Allergy and Immunology; Biological and medical sciences; Child; Child, Preschool; Fluorescent Antibody Technique, Direct - methods; Fundamental and applied biological sciences. Psychology; Hong Kong; Human viral diseases; Humans; Infant; Infectious Disease; Infectious diseases; Influenza A virus - isolation & purification; Medical sciences; Microbiology; Miscellaneous; Nasopharyngeal aspirates (NPA); Nasopharyngeal flocked swabs (NPFS); Nasopharynx - virology; Parainfluenza Virus 1, Human - isolation & purification; Parainfluenza Virus 2, Human - isolation & purification; Parainfluenza Virus 3, Human - isolation & purification; Rapid diagnosis; Respiratory syncytial virus; Respiratory Syncytial Viruses - isolation & purification; Respiratory Tract Infections - virology; Respiratory viruses; Reverse Transcriptase Polymerase Chain Reaction - methods; Sensitivity and Specificity; Specimen Handling - methods; Viral diseases; Virology; Virus Diseases - virology; Viruses - genetics; Viruses - isolation & purification; Hong Kong; Rapid diagnosis; Respiratory viruses; Nasopharyngeal aspirates (NPA); Nasopharyngeal flocked swabs (NPFS); Human; Microbiology; Samplings; Diagnosis; Child; Virology
• ISSN: 1386-6532; 1873-5967
• DOI: 10.1016/j.jcv.2007.12.003

Abstract Background The quality of clinical specimens is a crucial determinant for virological diagnosis. Objectives We compared the viral diagnostic yield for influenza A and respiratory syncytial virus (RSV) from the recently developed nasopharyngeal flocked swabs (NPFS) with nasopharyngeal aspirates (NPA) collected in parallel from 196 hospitalized children with acute respiratory infection during the peak period of influenza A and RSV activity in Hong Kong. Specimens were tested by RT-PCR for influenza A and RSV and viral load determined. They were also tested by direct immunofluorescence (DIF) for influenza A and B, RSV, parainfluenza types 1–3 and adenovirus. Results Both NPA and NPFS had excellent sensitivity (100%) for detecting influenza A by RT-PCR but NPA was slightly more sensitive than NPFS for detecting RSV by both RT-PCR (100% vs. 92.3%) and DIF (87.2% vs. 84.6%) and for detecting influenza A by DIF (90.2% vs. 82.9%). Viral load for influenza A in NPA and NPFS was not significantly different but that for RSV was higher in NPA. Conclusion NPA remains the optimal specimen for diagnosis of respiratory infections by RT-PCR and DIF. However, collection of NPFS is easier to perform in an out-patient setting, was more acceptable to parents and less likely to generate aerosols than NPA engendering potentially less infection control hazard.