Overview
Modifier 93 is a CPT (Level I) modifier, so its official wording belongs to the American Medical Association and is not reproduced here. In plain terms it says that a service was delivered synchronously, with the patient and practitioner talking in real time, over an audio-only connection such as a telephone call. The AMA added it to CPT for 2022, when payers that had relaxed telehealth rules during the COVID-19 public health emergency needed a way to tell audio-only care from video visits.
For Medicare, the governing instruction is chapter 26, section 10.5 of the Medicare Claims Processing Manual. A telehealth service is billed with place of service 02 when the patient is somewhere other than home or 10 when the patient is at home, and the place of service "must be paired with the appropriate telehealth modifier": 93 for audio only, 95 for audio and video. The same paragraph says the choice between 93 and 95 does not change the rate; only the place of service code decides between the facility and non-facility payment.
What 93 does not do is make a service eligible. Medicare covers audio-only delivery only where its telehealth rules allow it, which the physician fee schedule rules define and have changed several times since 2020, with behavioral and mental health services treated most broadly. The code itself must also be one Medicare allows as telehealth. Checking the current Medicare telehealth services list and the fee schedule rule for the year is therefore part of every audio-only claim.
HCPCS Level II has its own audio-only modifier, FQ, whose CMS descriptor is "the service was furnished using audio-only communication technology". Some Medicare billing instructions, for example for certain institutional and clinic claims, call for FQ rather than or alongside 93, so the contractor's instructions for the claim type decide which one appears. Commercial plans and Medicaid programs set their own audio-only policies; many recognize 93, some pay audio-only services at a different rate, and some do not cover them, which is why payer-level rules matter more for 93 than for most modifiers.
Documentation should state that the visit was audio-only, why video was not used when the payer requires a reason, where the patient was and how long the interaction lasted, because those facts support the place of service and the modifier together. Audio-only rules have changed from year to year, so a claim reviewed or appealed later is judged against the rule for its date of service.
Worked example
A psychiatrist holds a scheduled follow-up with an established patient at home by telephone, because the patient's internet connection cannot support video that day. The claim reports the visit code, place of service 10 for a patient at home and modifier 93. Medicare pays the non-facility rate, the same amount it would pay if the visit had used video, and the note records the audio-only modality, the patient's location and the time spent.
Look it up in CMS data
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Frequently asked questions — Modifier 93 (Audio-Only Service)
What is the difference between modifiers 93 and 95?
Both report a real-time telehealth service. Modifier 93 means the connection was audio only; modifier 95 means real-time audio and video. Medicare pairs either one with place of service 02 or 10, and neither changes the payment rate.
Does modifier 93 reduce Medicare payment?
No. The Claims Processing Manual says the audio-only or audio-video modifier does not change the rate; the place of service code alone decides between the facility rate (POS 02) and the non-facility rate (POS 10).
Which place of service code goes with modifier 93?
The one for the patient's location during the call: POS 10 when the patient is at home and POS 02 anywhere else. The practitioner's own location does not decide the code.
Should a claim use modifier 93 or FQ?
It depends on the claim type and payer. 93 is the CPT audio-only modifier; FQ is the HCPCS Level II modifier with the same meaning, which some Medicare billing instructions require. Follow the contractor's instructions for the claim form you are billing.
Disclaimer
This glossary entry is operational reference for revenue-cycle and medical-billing professionals. It is not legal, clinical, or contractual advice. Industry benchmarks cite named public sources where available; always verify against the current guidance from the authority body before relying on a number in a contract, policy, or compliance filing.