Not every audiogram produced during a hearing conservation program is a valid OSHA record. An audiogram conducted in a test environment that exceeds OSHA’s ambient noise limits, with an uncalibrated audiometer, or under conditions that produce unreliable results, may be invalid — and using it to make STS determinations creates compliance and liability problems. Understanding what makes an audiogram invalid, how to respond when one occurs, and how to document the situation protects both the program’s integrity and the employer’s compliance record. According to CDC/NIOSH, test environment and audiometer calibration are the most common sources of invalid audiometric results in occupational programs.
Causes of Audiogram Invalidity
- Test environment ambient noise: If background noise in the test room exceeds ANSI S3.1-1999 maximum permissible ambient noise levels at the test frequencies, the ambient noise may mask tones and produce falsely elevated (worse) thresholds. This is the most common technical cause of invalid occupational audiograms.
- Audiometer calibration failure: An audiometer that is out of calibration may produce inaccurate tone levels, generating false threshold shifts or masking genuine ones. Annual electroacoustic calibration and daily biologic checks detect this problem.
- Temporary threshold shift (TTS) contamination: For baseline audiograms, OSHA Appendix C recommends a 14-hour quiet period before testing. A baseline conducted shortly after significant noise exposure may reflect TTS rather than stable hearing status, artificially elevating the baseline thresholds.
- Worker response reliability: Some workers produce unreliable responses due to fatigue, inattention, language barriers, or deliberate exaggeration. The professional supervisor evaluates whether response patterns are consistent with a reliable test performance.
- Equipment malfunction: Transducer failures, headphone seal problems, and electronic issues can produce anomalous results. The daily biologic check is designed to catch obvious equipment malfunctions before a test session.
When a professional supervisor determines an audiogram is invalid, do not delete the invalid record from the HCP file. Retain it with a notation of the professional supervisor’s invalidity determination and the reason. The original invalid audiogram may be relevant if the HCP is later audited or if questions arise about the program’s quality during WC proceedings. Retaining the record with the invalidity determination documents that the problem was identified and addressed.
Responding to an Invalid Audiogram
When an audiogram is determined to be invalid:
- Document the professional supervisor’s invalidity determination and the reason (ambient noise, calibration, response reliability, etc.)
- Address the underlying cause before retesting (re-measure test environment ambient noise, confirm calibration status, schedule retest after adequate quiet period)
- Retest the worker under corrected conditions
- Retain both the invalid audiogram and the replacement audiogram in the HCP records
- Note that no STS determination can be made from the invalid audiogram
Most audiogram invalidity causes are preventable with proper program design: ANSI S3.1-1999 compliant test environments eliminate ambient noise invalidity; regular audiometer calibration eliminates equipment-based invalidity; the 14-hour quiet period before baseline audiograms prevents TTS contamination. Soundtrace’s program design addresses all three preventable causes at the system level rather than relying on post-hoc invalidity review.
Frequently Asked Questions
Audiometric Results Validated Before STS Determinations
Soundtrace Professional Supervisor review includes evaluation of audiogram validity — identifying results that require retesting before STS calculations rather than generating compliance decisions from invalid data.
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