Format

Send to

Choose Destination
Trop Med Int Health. 2002 Apr;7(4):317-21.

Comparison of nasopharyngeal aspirate and nasal swab specimens for detection of respiratory syncytial virus in different settings in a developing country.

Author information

1
Projecto de Sa├║de de Bandim, Bissau, Guinea-Bissau. lgn@ssi.dk

Abstract

OBJECTIVE:

To compare detection of respiratory syncytial virus (RSV) for diagnostic purposes using nasopharyngeal aspirate (NPA) and nasal swabs (NS) in different clinical settings in a community study in Guinea-Bissau.

METHOD:

During 1996-98 paired specimens were obtained from 635 children under 5 years of age (median: 274 days; interquartile range: 144-453 days) with symptoms of lower respiratory infections (LRI). The specimens were analysed by an enzyme-linked immunosorbent assay for RSV antigen in Guinea-Bissau and re-analysed in Denmark using the same assay. The gold standard for RSV antigen detection was defined as any test being positive.

RESULTS:

RSV antigen was detected in 84 (13%) children, the prevalence being 19% (41/219) among infants aged < 6 months, 12% (22/184) in infants aged 6-11 months, and 9% (21/230) in older children. Sensitivity of antigen detection was higher in NPA (92% in analyses in Guinea-Bissau and 98% in Denmark) than in NS (63% in analyses in Guinea-Bissau, 71% in Denmark). Specificity of RSV antigen detection was equally high in NPA and NS (99-100%). Time since onset of symptoms was significantly shorter in RSV antigen positive than negative samples. Sensitivity did not depend on clinical setting or age of the child.

CONCLUSION:

Using NS samples was associated with a 27-31% reduction in sensitivity compared with NPA specimens. As NPAs are costly and considered a nuisance by the population, it might be cost-effective in larger epidemiological studies to lose 25-30% in sensitivity but be able to collect samples from a much larger population.

[Indexed for MEDLINE]
Free full text

Supplemental Content

Full text links

Icon for Wiley
Loading ...
Support Center