To the Editor: In their Rational Clinical Examination article about the diagnosis of Bordetella pertussis in coughing patients, Dr Cornia and colleagues1 found that the classic symptoms of posttussive emesis and inspiratory whoop have limited clinical value. In diagnostic decision making, more important than the test characteristics of any sign, symptom, or diagnostic test is the pretest probability (prevalence) of the diagnosis in question.
Linder JA. Diagnosis of Pertussis. JAMA. 2010;304(21):2358-2359. doi:10.1001/jama.2010.1725