To the Editor.
—Schapira et al1 executed an excellent study of the FET in the diagnosis of obstructive airways disease. However, we are concerned about the reproducibility of the maneuver.We studied four internists examining 92 patients, yielding 342 examinations.2 As in the study of Schapira et al, we used blinded, board-certified internists, who measured the FET while listening to the trachea with a stethoscope. We also trained our clinicians prior to the study by examining model patients. Unlike the study of Schapira et al, our examiners measured the FET with ordinary wristwatches, rather than stopwatches, and recorded the time to the nearest half second.When we analyzed our data using the spirometric and FET criteria of Schapira et al, we found that 38% of patients had airway obstruction. The κ statistic for measuring interphysician agreement was 0.27. When we explored the reason for only "fair agreement" between
Badgett R, Tanaka D. The Diagnostic Value of the Forced Expiratory Time. JAMA. 1994;271(1):25. doi:10.1001/jama.1994.03510250041023