What test is diagnostic for Bordetella pertussis infection?

What test is diagnostic for Bordetella pertussis infection?

• A. Nasal swab culture for Bordetella pertussis
• B. Chest X-ray
• C. CBC
• D. Rapid influenza test

Answer: (A)

Testing for Bordetella pertussis relies on directly identifying the organism from the patient’s respiratory secretions. The most definitive way is to obtain a nasopharyngeal specimen and culture it on selective media designed for B. pertussis. This isolates the bacteria and confirms infection. PCR on a nasopharyngeal specimen is also used and can be faster and highly sensitive, especially early in the illness, but culture remains the traditional benchmark for a positive diagnosis. The other options aren’t diagnostic for pertussis: chest X-ray can show non-specific findings, a CBC may show lymphocytosis but is not specific, and a rapid influenza test targets influenza viruses, not pertussis.

Testing for Bordetella pertussis relies on directly identifying the organism from the patient’s respiratory secretions. The most definitive way is to obtain a nasopharyngeal specimen and culture it on selective media designed for B. pertussis. This isolates the bacteria and confirms infection.

PCR on a nasopharyngeal specimen is also used and can be faster and highly sensitive, especially early in the illness, but culture remains the traditional benchmark for a positive diagnosis.

The other options aren’t diagnostic for pertussis: chest X-ray can show non-specific findings, a CBC may show lymphocytosis but is not specific, and a rapid influenza test targets influenza viruses, not pertussis.