Audiometry·OSHA Compliance·14 min read·Updated March 2026
When your hearing conservation vendor returns the annual audiogram results, what comes back is not just a set of numbers — it is a PLHCP report containing clinical language that directly determines your specific OSHA obligations for each worker. “STS confirmed, no revision recommended.” “Asymmetric sensorineural loss, medical referral advised.” “Non-work-related; no 300 Log entry required.” Safety managers who can parse these findings accurately know exactly what follow-up is required, what is optional, what can wait, and what must happen within 21 days. Safety managers who can’t are at risk of missed notifications, undocumented referrals, and OSHA 300 Log entries that were never made — or were made when they shouldn’t have been. This guide translates every common PLHCP finding into plain-English employer obligations.
Soundtrace provides PLHCP-reviewed audiometric reports with findings translated into specific employer action items — so the compliance step is never in question.
What the PLHCP Does — and What They Don’tThe PLHCP reviews audiometric results and provides findings. They determine whether an STS occurred, whether it appears permanent, whether it appears work-related, and what follow-up is recommended. The employer is responsible for the compliance actions that follow. A PLHCP recommendation is not self-executing — the 21-day notification clock, the HPD refitting, and the 300 Log entry are employer obligations that depend on the employer correctly interpreting the PLHCP’s report.
Who Is the PLHCP?
Under 29 CFR 1910.95, the Professional Licensed in Health Care Practice (PLHCP) is the physician or audiologist responsible for reviewing occupational audiometric test results and providing the employer with specific findings and recommendations. The PLHCP may be a licensed physician (MD or DO), an otolaryngologist, or a certified audiologist. Their role is clinical review — they evaluate the audiometric data, apply professional judgment about what the data means, and report that judgment to the employer.
The occupational hearing conservationist (OHC) — the technician who actually conducts the audiometric testing — is a different person. An OHC is a certified technician who administers pure-tone air conduction audiometry. They can conduct tests and flag apparent results, but the PLHCP provides the official findings. Employers are legally required to act on PLHCP findings, not on OHC technician observations.
OSHA requires that the PLHCP provide findings in writing to the employer for each audiogram showing an STS or other significant finding. The employer is then responsible for taking the specific actions that OSHA requires in response to those findings.
What the PLHCP Reviews and Determines
For each audiogram, the PLHCP evaluates:
- STS status: Has the worker’s hearing changed by 10 dB or more (average at 2000/3000/4000 Hz) compared to their baseline? Is that shift a true permanent threshold shift or possibly TTS-related?
- Work-relatedness: Is the hearing loss or shift attributable to occupational noise exposure? This affects OSHA 300 Log recordability.
- Need for medical referral: Does the audiogram show findings that warrant evaluation by a physician or otolaryngologist (e.g., asymmetric loss, sudden changes, conductive components, low-frequency loss)?
- Baseline revision recommendation: Should the baseline audiogram be revised upward (to reflect confirmed PTS) or downward (to reflect an improved retest)?
- Fitness for duty or HPD adequacy: In some programs, the PLHCP may comment on whether the worker’s current HPD selection is appropriate for their noise exposure and audiometric status.
Anatomy of a PLHCP Audiogram Report
Figure 1 — Anatomy of a PLHCP Audiogram Report
The five sections of a standard PLHCP report and what each one means for employer compliance obligations.
Report Section
What It Contains
Employer Action Trigger?
STS Finding
Whether an STS occurred and whether it appears to be a permanent shift; may include age-corrected result
Yes — notify within 21 days; refit HPDs; retest option
Work-Relatedness
Whether the PLHCP believes the loss is work-related, non-work-related, or unable to determine without further evaluation
Yes — determines 300 Log recording obligation
Medical Referral Recommendation
Whether the worker should be referred to a physician or otolaryngologist; may specify urgency
Yes if STS persists; may be required if shift confirmed
Baseline Revision Recommendation
Whether to revise the worker’s baseline audiogram upward (confirmed PTS) or downward (improvement confirmed)
Optional — employer decision; must be documented
Additional Clinical Notes
Observations about audiogram pattern, asymmetry, low-frequency involvement, conductive findings, or ototoxicity concern
Follow-up per specific note; may require program review
Finding Decoder: Every Common PLHCP Result Translated
Figure 2 — PLHCP Finding Decoder
Plain-English translation of every common clinical phrase in a PLHCP audiogram report, and the specific employer action each triggers.
PLHCP Language
Plain English
Mandatory Actions
Timeline
“No STS. Within normal limits.”
Hearing unchanged from baseline; no shift detected
None required
N/A; file in record
“STS confirmed. No revision recommended.”
Permanent 10+ dB average shift detected; PLHCP is not recommending updating the baseline
Notify employee; refit HPDs; retraining; evaluate 300 Log
Notify within 21 days
“STS confirmed. Baseline revision recommended.”
Confirmed permanent shift; PLHCP recommends updating baseline to current audiogram
Same as above + execute revision if chosen; document
Notify within 21 days
“STS confirmed. Medical referral recommended.”
Confirmed permanent shift; audiogram pattern warrants physician evaluation
All STS actions + arrange physician referral; document referral and outcome
Notify within 21 days; referral promptly
“Apparent STS; recommend retest.”
Shift detected but may reflect TTS or test variability; retest before confirming
Notify employee; refit HPDs; schedule retest within 30 days
Notify within 21 days; retest within 30
“STS resolved on retest. No current STS.”
30-day retest showed original shift was TTS or variability, not permanent
No 300 Log required; file retest; consider HPD review
File and document
“Improvement noted. Baseline revision recommended.”
Retest shows better hearing than baseline; may indicate prior baseline was TTS-contaminated
Revise baseline downward if elected; document; review baseline validity
Document and file
“Asymmetric sensorineural loss. Medical referral advised.”
One ear significantly worse than the other; raises concern for non-noise causes (e.g., acoustic neuroma) that require medical evaluation
Arrange physician/otolaryngologist evaluation; document referral; follow up on outcome
Promptly
“Low-frequency hearing loss noted. Medical referral recommended.”
NIHL and presbycusis primarily affect high frequencies; low-frequency loss suggests a non-noise cause (Meniere’s, autoimmune, medication) requiring evaluation
Medical referral; document; determine work-relatedness after evaluation
Promptly
“Conductive component present. Refer for medical evaluation.”
Air-bone gap indicates middle ear pathology (fluid, ossicular problem, perforation) that is treatable and not NIHL — needs medical evaluation
Refer to physician/ENT; do not count as noise-related STS until cleared; document all steps
Promptly
“Work-relatedness cannot be determined without further evaluation.”
The PLHCP cannot make a work-relatedness determination from the audiogram alone; a physician evaluation is needed before the employer can determine 300 Log recordability
Refer to physician; defer 300 Log entry until determination made; document process
Within reasonable time
“Consistent with noise-induced pattern. No current STS.”
Audiogram shows 4 kHz notch typical of NIHL, but no shift from baseline has occurred yet — no STS trigger currently
No immediate OSHA action required; review HPD program; monitor closely
No deadline; program review
STS Findings in Detail: What Each Variant Means
The STS finding is the most consequential section of the PLHCP report. There are four variants, each with different employer obligations:
Figure 3 — STS Finding Variants and Employer Response
Every possible STS-related PLHCP finding and the specific compliance path it requires.
Variant A
STS Confirmed, Permanent
PLHCP has determined the 10+ dB average shift is a true permanent threshold shift, not TTS or test variability.
Required actions:
1. Notify employee in writing — within 21 days
2. Refit and retrain on HPDs — promptly
3. Evaluate 300 Log recordability
4. Medical referral if recommended
Variant B
Apparent STS, Retest Recommended
Shift detected but PLHCP suspects TTS or variability. Employer may retest within 30 days and use retest in place of annual.
Required actions:
1. Notify employee — within 21 days (still required)
2. Refit HPDs
3. Retest within 30 days
4. If retest clears: no 300 Log entry
5. If retest confirms: full Variant A path
Variant C
STS Confirmed + Medical Referral
Confirmed permanent shift with an audiogram pattern that the PLHCP believes warrants physician evaluation (asymmetric, conductive component, unusual pattern).
Required actions:
1. All Variant A actions
2. Arrange physician referral — promptly
3. Document referral date and physician response
4. Revisit 300 Log entry after physician finding
Variant D
STS + Non-Work-Related Finding
Confirmed shift but PLHCP determines it is not work-related (e.g., purely age-related, pre-existing, or medical cause unrelated to occupational noise).
Required actions:
1. Notify employee — within 21 days (still required)
2. Refit HPDs
3. No 300 Log entry (not work-related)
4. Document PLHCP non-work-relatedness determination
Medical Referral Findings: When They’re Required vs. Recommended
OSHA distinguishes between cases where medical referral is required and cases where it is recommended by the PLHCP. The distinction matters for compliance and documentation:
- Required referral: Under 29 CFR 1910.95(g)(7), if an STS is confirmed on the 30-day retest (or if no retest is conducted), the employer must refer the employee to a physician or audiologist for further evaluation. This is a mandatory obligation, not a recommendation.
- PLHCP-recommended referral (non-STS): The PLHCP may recommend medical evaluation even when no STS has occurred — for example, when they observe asymmetric loss, low-frequency involvement, a conductive component, or a pattern inconsistent with typical NIHL. These recommendations are not strictly required by OSHA but should be treated as mandatory for two reasons: (1) ignoring a documented clinical recommendation creates liability if the worker later develops a related condition; (2) the recommendation is in writing in the audiometric record.
The Documentation TrapIf a PLHCP recommends medical referral in writing and the employer does not act on that recommendation, the employer has a documented recommendation sitting in the audiometric file with no corresponding action. In a WC claim or OSHA investigation, that gap is visible and damaging. Treat every written PLHCP recommendation as a required action until documented as complete.
Figure 4 — Medical Referral: Required vs. Recommended
Know when a referral is an OSHA hard requirement vs. a PLHCP recommendation — and why the practical response is the same either way.
Trigger
Required or Recommended?
OSHA Citation Risk if Missed
Documentation Needed
STS confirmed on 30-day retest or no retest conducted
Required by OSHA
High
Referral date; physician name; findings received
PLHCP notes asymmetric loss
PLHCP Recommended
Moderate (documented recommendation ignored)
Referral arranged; outcome documented
PLHCP notes conductive component
PLHCP Recommended
Moderate to high
Referral and outcome documented
PLHCP notes low-frequency loss
PLHCP Recommended
Moderate (ignored recommendation in record)
Referral and physician findings
A PLHCP determination that hearing loss is not work-related has significant consequences: the employer is not required to record the case on the OSHA 300 Log, and the employer’s WC exposure for that loss may be reduced. But a non-work-related determination is not a clean exit from all obligations.
- STS notification is still required even if the PLHCP determines the shift is not work-related. The STS notification obligation under 1910.95(g)(8) applies when an STS occurs, regardless of work-relatedness. Work-relatedness only affects 300 Log recordability, not STS response obligations.
- The HPD refit and retraining are still required. Whether the shift is from noise or aging, the worker is a noise-exposed employee in your program. Their HPD status must be reviewed.
- The PLHCP’s determination can be contested. If OSHA disagrees with a non-work-related determination, the employer needs supporting documentation from the PLHCP explaining the basis for the determination. A bare “non-work-related” notation without clinical reasoning is harder to defend.
Baseline Revision Recommendations: A Decision, Not an Automatic Update
When the PLHCP recommends baseline revision, the employer must make a deliberate decision about whether to revise and must document that decision. Revision is permitted, not required. The PLHCP’s recommendation is a clinical opinion — it does not automatically revise the baseline. The employer (in coordination with the PLHCP) must execute the revision and update the audiometric file to reflect which audiogram now serves as the current baseline.
The downstream consequences of revision are significant. See Baseline Audiogram Contamination for a detailed analysis of what baseline revision gains and loses in terms of STS detection and WC defense.
Employer Action Matrix: What Each Finding Requires
Figure 5 — Complete Employer Action Matrix by PLHCP Finding
Check marks indicate required actions. Timelines are OSHA-specified unless noted as “promptly” (reasonable diligence standard).
PLHCP Finding
Notify worker
Refit HPDs
30-day retest
Med. referral
300 Log eval
Baseline revision
STS confirmed
✓ 21d
✓
opt.
✓ if persists
✓
opt.
Apparent STS, retest recommended
✓ 21d
✓
✓ 30d
if persists
after retest
opt.
STS + medical referral
✓ 21d
✓
opt.
✓ req.
✓
opt.
STS, non-work-related
✓ 21d
✓
opt.
if noted
✗ no entry
opt.
Asymmetric loss, no STS
—
—
—
✓ rec.
—
—
Documentation Requirements: What Must Be in the Audiometric File
OSHA requires that audiometric records be maintained for the duration of employment. The audiometric file for each worker must contain:
- The worker’s name, job classification, and noise exposure data
- All audiograms conducted during employment (baseline and all annuals)
- The PLHCP’s written findings and recommendations for each audiogram
- Records of all employer actions taken in response to PLHCP findings (notification dates, HPD refitting dates, referral dates and outcomes)
- Documentation of any baseline revisions (original baseline retained, new baseline identified, date and basis for revision)
- OSHA 300 Log entries for recordable hearing loss cases
Documentation Rule of ThumbEvery PLHCP finding creates a documentation obligation. If the PLHCP says “STS confirmed” — document the notification date. If the PLHCP says “medical referral recommended” — document the referral and outcome. If the PLHCP says “no revision recommended” and the employer decides to revise anyway (or not) — document the decision and the basis. The audiometric file should allow a third party to reconstruct exactly what the PLHCP found and exactly what the employer did in response, with dates.
Frequently asked questions
What is a PLHCP in a hearing conservation program?
A PLHCP (Professional Licensed in Health Care Practice) is the physician or audiologist who reviews audiometric results in an OSHA-compliant hearing conservation program. Their written findings determine the employer’s specific compliance obligations — whether an STS has occurred, whether it is work-related, whether medical referral is needed, and whether baseline revision is appropriate.
What does “STS confirmed, no revision recommended” mean?
STS confirmed means the shift is a true permanent threshold shift, not TTS or test variability. No revision recommended means the PLHCP does not suggest updating the baseline to the current audiogram. The employer still has all standard STS obligations: notify within 21 days, refit HPDs, evaluate 300 Log recordability, and refer to physician if the shift persists on retest.
Does a non-work-related PLHCP determination eliminate all OSHA obligations?
No. A non-work-related determination eliminates the OSHA 300 Log recording obligation only. The STS notification (within 21 days), HPD refitting, and retraining obligations apply regardless of work-relatedness. The non-work-related determination must be documented in the audiometric file, and the employer should retain the PLHCP’s clinical reasoning in case of a subsequent OSHA review or WC claim.
What does “asymmetric sensorineural loss” mean and what should the employer do?
Asymmetric sensorineural loss means significantly different hearing thresholds between the two ears. While NIHL typically produces bilateral, roughly symmetric loss, asymmetric loss raises the question of non-occupational causes such as acoustic neuroma, single-sided trauma, or certain medical conditions. When the PLHCP notes this finding, the employer should arrange medical evaluation and document the referral and its outcome.
Is the employer required to act on all PLHCP recommendations?
OSHA-required actions (STS notification, HPD refitting, medical referral after confirmed STS) must be performed regardless of whether the PLHCP mentions them. For PLHCP-recommended actions (referral for asymmetric loss, baseline revision suggestions), the employer should treat them as effectively required: ignoring a written recommendation that sits in the audiometric file creates documented liability if the worker later develops a related condition or files a WC claim.
PLHCP-Reviewed Results with Clear Action Items
Soundtrace provides audiometric results reviewed by licensed audiologists, with each finding translated into specific employer actions — so the compliance step is never ambiguous.
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