Fine flexible wire swab or aspirate with direct smear where appropriate.
Suspected pertussis (whooping cough);
severe bronchiolitis in infants;
investigation of severe respiratory infection (including pneumonia), particularly if viral infection is suspected.
Diagnosis of whooping cough can be confirmed by detection of Bordetella pertussis after amplification.
See also Virus detection.
Carroll KC. J Clin Microbiol. 2002; 40: 3115-3120.