SLP CPT Codes: The Working Reference for Speech Therapy Billing

CPT codes are how the work you did becomes the money your employer collects. Most SLPs learn them by osmosis in their first job, badly, and then spend years guessing. This is the working list — what each code covers, whether it is timed, and the pairing rules that cause most denials.

Evaluation codes

• 92521 — evaluation of speech fluency (stuttering, cluttering)
• 92522 — evaluation of speech sound production (articulation, phonological process, apraxia, dysarthria)
• 92523 — evaluation of speech sound production with evaluation of language comprehension and expression. This is the workhorse pediatric code; do not bill 92522 and 92523 together, because 92523 already includes the sound production component.
• 92524 — behavioral and qualitative analysis of voice and resonance
• 92610 — evaluation of oral and pharyngeal swallowing function (the clinical/bedside swallow evaluation)
• 92611 — motion fluoroscopic evaluation of swallowing (MBSS), reported by the SLP for the SLP's portion; radiology bills separately
• 92612 / 92613 — FEES with interpretation and report (92613 is the interpretation-and-report-only component)
• 92614 / 92615, 92616 / 92617 — laryngeal sensory testing and FEESST variants
• 96105 — assessment of aphasia with a standardized instrument, billed per hour (this one is timed)
• 96125 — standardized cognitive performance testing, per hour, including interpretation and report

Evaluation codes other than 96105 and 96125 are untimed session codes: you bill one unit regardless of whether the evaluation took 45 minutes or 90.

Treatment codes

• 92507 — treatment of speech, language, voice, communication, and/or auditory processing disorder, individual. Untimed, one unit per session.
• 92508 — the same treatment delivered in a group of two or more. Untimed, billed per patient.
• 92526 — treatment of swallowing dysfunction and/or oral function for feeding. Untimed.
• 92520 — laryngeal function studies.
• 92597 — evaluation for use and/or fitting of a voice prosthetic device.
• 92607 / 92608 — evaluation for prescription of a speech generating device; 92607 is the first hour, 92608 each additional 30 minutes (timed).
• 92609 — therapeutic services for the use of a speech generating device, including programming and modification. Untimed.
• 31579 — laryngoscopy, flexible or rigid, with stroboscopy.
• 97129 / 97130 — therapeutic interventions that focus on cognitive function. 97129 is the first 15 minutes, 97130 each additional 15 minutes. These are timed and follow the 8-minute rule.
• 92610 vs. 92526: evaluation versus treatment. Billing 92526 on the same day as the swallow evaluation for the same encounter invites a denial unless documentation clearly separates the services.

Timed vs. untimed and the 8-minute rule

Most SLP codes are untimed service-based codes: one unit per session, regardless of duration. The timed exceptions in a typical SLP scope are 96105, 96125, 92607/92608, and 97129/97130. For those, Medicare's 8-minute rule applies: a single unit requires at least 8 minutes of one-on-one time, two units require 23 minutes, three require 38, four require 53. Bill only skilled treatment minutes — not setup, not documentation, not rest breaks.

Even on untimed codes, always document start and stop times or total treatment minutes. Auditors look for it, and payers increasingly require it to substantiate that a service occurred at all.

Modifiers you will actually use

• GN — services delivered under a speech-language pathology plan of care. Required on every SLP line for Medicare Part B. GP is physical therapy and GO is occupational therapy; using the wrong one is a fast denial.
• KX — attests that services above the annual therapy threshold are medically necessary and supported in the record. See the Medicare Part B guide.
• 59 / XE, XS, XP, XU — distinct procedural service, to unbundle codes that are otherwise NCCI edit pairs. Use only when the services genuinely were separate.
• 95 or GT — telehealth delivery, with place-of-service coding per payer.
• GA / GY / GZ — ABN and non-covered service attestations.
• CQ — services furnished in whole or part by a speech-language pathology assistant where the payer recognizes them (rules vary by payer and state).

NCCI edits and common bundling traps

The National Correct Coding Initiative defines which code pairs cannot be billed together and how many units of a code are plausible in a day (Medically Unlikely Edits). The traps SLPs hit most:

• 92522 with 92523 on the same day for the same patient
• 92507 with 92526 without documentation separating the communication and swallowing work
• Multiple units of an untimed code for a longer session
• 92610 billed alongside an instrumental study for the same swallow assessment episode

Diagnosis coding

CPT says what you did; ICD-10-CM says why. Code to the highest specificity available and make sure the diagnosis supports medical necessity for the CPT code billed. Frequently used families include R47.x (speech disturbances, including aphasia and dysarthria), R48.2 (apraxia), F80.x (developmental speech and language disorders), R13.1x (dysphagia by phase), R49.x (voice disturbances), and I69.x (sequelae of cerebrovascular disease). A stroke sequela code paired with a dysphagia code tells the payer the whole story; F80.0 alone on an adult claim does not.

Setting matters

CPT is used in outpatient, private practice, and Part B settings. Inpatient rehab and skilled nursing facilities operate under prospective payment systems (IRF-PAI, PDPM), where minutes and functional scoring drive reimbursement rather than individual CPT lines. Early intervention and school services generally bill under Medicaid or IDEA rather than commercial CPT rules — see the school Medicaid billing guide.

Practical habits that prevent denials

• Verify benefits and visit limits before the evaluation, not after visit six.
• Match the CPT code to what the plan of care authorizes.
• Document skilled service language, not activity logs — see the SOAP note guide.
• Keep a payer-specific cheat sheet; commercial plans deviate from Medicare constantly.
• Re-check the CPT and ICD-10 code sets each January; codes are revised annually.

Coding and coverage rules change annually and vary by payer and state. Verify current requirements with your payer, your billing department, and ASHA's coding resources before submitting claims.