Studies show that using nasopharyngeal aspiration to collect specimens yield the highest sensitivities in viral and bacterial tests.

“Nasopharyngeal specimen collection was less traumatic for the patient,was an easier procedure for the physician to perform, and provided a superior laboratory specimen for RSV diagnosis than the nasopharyngeal swab technique.”

Ahluwalia G, Embree J, McNicol P, Law B, Hammond G. Comparison of nasopharyngeal aspirate and nasopharyngeal swab specimens for respiratory syncytial virus diagnosis by cell culture, indirect immunofluorescence assay, and en zyme-linked immunosorbent assay.

J Clin Microbiol. 1987 May;25(5):763-7.