Which specimen type is the preferred specimen for Bordetella pertussis detection?

• A. Nasopharyngeal swab
• B. Anterior nares swab
• C. Blood
• D. Sputum

Answer: (A)

Bordetella pertussis is most reliably detected from the nasopharynx because the organism colonizes the upper airway there early in infection, so a specimen from the posterior nasopharynx carries the highest amount of organism and yields the best test sensitivity. Collecting with a flexible swab and rotating it to pick up mucosal secretions, then sending the sample in appropriate transport media (for culture or PCR), maximizes the chance of detection. Anterior nares swabs sample only the front part of the nasal cavity and have substantially lower sensitivity for pertussis. Blood is not a typical source of the organism in pertussis testing, since bacteremia is not a standard feature, and sputum, while possible, often provides variable quality and can be contaminated with normal oropharyngeal flora, making detection less reliable. So the nasopharyngeal swab stands out as the best option for accurate Bordetella pertussis detection.