Rapid diagnostic tests exist for several pathogens currently linked to acute bronchitis. However,not all the rapid tests are widely available, and their routine use is not cost-effective in an outpatient setting. Rapid tests should be used primarily when the suspected organism is treatable, the infection is known to be circulating in the community, and the patient has suggestive symptoms or signs (e.g., testing for influenza during influenza season in patients with cough and fever) (Table 1).Multiplex polymerase-chain-reaction (PCR) testing of nasopharyngeal swabs or aspirates is being developed to diagnose infections resulting from B. pertussis, M. pneumoniae, or C. pneumoniae with clinically useful sensitivity and specificity, as compared with culture or monoplex PCR.