A three-frequency audiogram for use in industry.

Some form of audiometric screening forms part of any comprehensive hearing conservation programme, but because of the large numbers of workers exposed to noise, it is suggested that routine audiometry using an 8-frequency test preceded by history and examination makes undue demands on limited resources. It is proposed that a simple 3-frequency test without prior preparation of subjects is adequate for the purposes of industrial audiometry. Men whose hearing threshold was worse than 20 dB at 1, 2, or 4 kHz were considered to have failed the 3-frequency test and 150 such cases were randomly selected and subjected to a full 8-frequency audiogram. The results were then assessed for numerical accuracy and diagnostic reliability. The results of the 3-frequency test were marginally worse than the 8-frequency audiogram by 2.33 to 4.98 dB, and the comparison of the two tests as a diagnostic tool gave a concordance rate of 79%-80% (p = 0.00001) between the two physicians who examined the results and a level of interpersonal agreement of 87% for the 3-frequency test and 89% for the full audiogram. If audiometric screening is to be offered to the whole population at risk it should be simple, rapid, and accurate enough to detect hearing loss before disability develops so that those individuals may be counselled. It is suggested that the 3-frequency test fulfils this purpose, demonstrates the "reasonably practicable" approach of recent legislation, and does not unnecessarily divert resources from other key tasks in the practice of occupational medicine.