PEAK EXPIRATORY FLOW MONITORING IS NOT A RELIABLE METHOD FOR ESTABLISHING THE DIAGNOSIS OF OCCUPATIONAL ASTHMA

This is a study of the reliability of peak expiratory flow (PEF) monit oring using a portable computerized peak flow meter, the VMX Mini-Log, in 17 subjects referred for suspected occupational asthma. Subjects w ere requested to monitor their PEF six times daily using the VMX Mini- Log for 2 wk at work and at least 10 d away from work. They were unawa re that their readings were stored by the flow meter in addition to th e digital readout. Four subjects (22%) were unable to complete the mon itoring. The results recorded by the subjects were compared with the r esults recorded by the VMX. Of those who completed the monitoring, onl y 55.3% of the records were completely accurate in terms of the value and the timing of the measurements, 23.3% were inaccurate either in te rms of the recorded value or of the timing of the measurement, and the remainder were fabricated results (not recorded by the Mini-Log). Our results suggest that PEF monitoring using ordinary peak flow meters f or assessment of work-relatedness of asthma has limitations and is not reliable.