When using personal noise monitoring , proper positioning of the microphone is necessary to obtain accurate measurements. With a dosimeter, the microphone is generally located on the shoulder and remains in that position for the entire workday. With a sound level meter, the microphone is located near the employee's head, and the instrument is usually held by an individual who follows the employee as he or she moves around the workplace. To make sure that results are accurate, instruments should be calibrated before and after each use. In addition, annual outside calibration is required, and records of the calibration must be kept.
Audiograms test each ear to determine an employee's hearing threshold at specific frequencies.
A physician . These professionals, along with trained technicians, may conduct the actual audiometric testing, and the professional does not have to be present when a qualified technician is conducting testing. However, the audiologist, otolaryngologist or physician has the responsibility of overseeing the program and the work of the technicians, reviewing problem audiograms and determining whether referral to additional medical care is necessary. The baseline audiogram serves as a comparison for future audiograms, helping determine hearing improvement or loss. An annual audiogram must be conducted within one year of the baseline audiogram.