What is a standard threshold shift?
A standard threshold shift (STS) is an adverse change in hearing thresholds when compared to the referent baseline audiogram of an average of 10 dB or more at 2000, 3000, and 4000 Hz in either ear. In determining whether a standard threshold shift has occurred, allowance may be made for the contribution of aging (presbycusis) to the change in hearing level by correcting the annual audiogram according to the procedure described in Appendix F: “Calculation and Application of Age Correction to Audiograms” of the OSHA 29 CFR 1910.95 regulation.
