Further, study and control subjects were categorized according
to their age, height, weight, body surface area and duration of exposure to wood dust. PEFR was determined by using a Mini
Wright’s peak flow meter. The testing procedure was quite simple and non–invasive and it was harmless to the patients. It was explained to subjects, followed by a demonstration of its performance. The test was done with the subjects in standing position. The subjects were instructed to take a maximal inspiration and to blow into the instrument rapidly and forcefully. A close watch was made to ensure that a tight seal was maintained between the lips and mouthpiece of the device. The test was repeated 3 times and the highest of these readings was considered for the purpose of analysis as litre/min. All the observations of age, height, weight, body surface area and PEFR were recorded in the proforma.