You finished the session, you wrote a clean note, you submitted the claim on time. And it still came back stamped "not medically necessary." If you supervise students, you've probably written that same phrase in the margin of a note that documented good, careful therapy. That's the frustrating thing about medical necessity speech therapy documentation: the care was skilled, the writing just didn't show it.
Medical necessity is something you prove on paper, not something a payer assumes because a licensed SLP was in the room. The good news is that proving it is a habit you can build. This guide walks through what payers actually mean by medical necessity, the skilled versus unskilled language that decides claims, how to write goals and progress notes that hold up, what to do when a claim gets denied, and why all of this matters even more once the new 2027 timed codes arrive.
What Payers Actually Mean by Medical Necessity
Start with the definition, because most SLPs have never seen it written down plainly. ASHA points to the Affordable Care Act language: medically necessary services are those needed to prevent, diagnose, or treat an illness, injury, condition, disease, or its symptoms, including habilitation, that meet accepted standards of practice.1 That word "habilitation" matters. It means care to build a skill the patient never had, not just restore one they lost, so the pediatric caseload counts every bit as much as the adult stroke patient.
Underneath the definition, payers apply a two-part test. Is the service reasonable, meaning the amount, frequency, and duration make sense for the diagnosis? And is it necessary, meaning it's the appropriate treatment for this patient's condition?2 Medicare adds its own framing: to be covered, SLP services have to be skilled and rehabilitative, requiring the knowledge and judgment of a speech-language pathologist.3
Here's the practical catch. SLP medical necessity isn't defined identically by every payer, and private plans vary the most.1 The smart move is writing to the payer's own definition rather than a generic one, because that's the standard your note will actually be judged against.
Skilled vs. Unskilled: The Language That Decides the Claim
This is where most denials are won or lost. ASHA is blunt about it: skilled services that aren't documented as skilled can look unskilled, and unskilled care isn't reimbursable.4 So the denial often isn't a judgment on your treatment. It's a judgment on your note.
What makes documentation read as skilled? A few things working together. You use terminology that reflects your clinical knowledge. You report objective data like accuracy, cue level, response time, and independence. You describe the specific cueing and feedback you provided, the decisions you made in the moment, and how a modification changed the patient's function.4 Anyone can write down a percentage. Only the clinician can explain the reasoning behind it.
Compare two versions of the same motor speech session. The unskilled note says: "Patient continues to present with unintelligible speech. Practiced conversation." The skilled note says: "Intelligibility 60% at the single-word level, 30% at phrase level. Patient benefits from clinician cues to reduce speech rate and limit utterances to one or two words."4 Same treatment. Only the second one shows an SLP was needed.
It works the same way for language and aphasia goals. "Patient produced word-level responses with 70% accuracy" is thin. Add the clinical picture, that the patient responds to concrete wh- questions at 70% but drops to 50% on abstract ones and benefits from phonemic cues yet can't self-cue, and now the note demonstrates skilled service documentation SLP reviewers can defend.4
When you're not sure which side of the line a note falls on, use this gut check: if a caregiver or an aide could have run the session exactly as you wrote it, the note doesn't show skilled care. Add back the judgment you actually used.
Writing Goals and Progress Notes That Support Necessity
Goals are the anchor for everything else, so write them functional and measurable, not as activity counts. "Complete 20 trials of /s/" tells a payer nothing about why the work matters. "Produce /s/ in conversation with 80% accuracy so unfamiliar listeners understand the patient" ties the target to real communication, which is what medical necessity is about.
Three things should be visible in every SOAP note you write: the diagnosis, the patient's current functional impairment, and the named intervention that connects to that impairment. When those three line up, a reviewer can follow the logic from problem to treatment without guessing. When one is missing, the claim gets shaky.
Then there's the progress report, which carries more weight than clinicians often realize. It's the justification for continued treatment, the document that answers "why keep going?"5 Write it to show change that's clearly attributable to your skilled intervention. And when progress is slow, don't hide it. Explain why continued skilled care is still needed, because a plateau with a clear clinical rationale is defensible while a plateau with no explanation is a denial waiting to happen. Always tie the current status back to baseline so the reviewer sees a trajectory instead of a single snapshot.
When a Claim Is Denied: Justifying Speech Therapy to Insurance
Even solid notes get denied sometimes, so justifying speech therapy to insurance after the fact is a skill worth having. Start by reading the denial closely. Does it cite a specific clinical criterion, or does it just say "not medically necessary" and leave it there?
If it names a criterion, answer that criterion directly. Document what was tried, how long it ran, and why it wasn't enough to meet the goal without continued skilled care. Give the reviewer the exact information the denial asked for.
If the denial is vague, treat it as the weak denial it is. Point back to the payer's own definition of medical necessity and walk through how the record already meets it: the diagnosis, the ICD-10 codes, the functional impairment, the goals, and the progress data.1 You're not making a new argument. You're showing the note already made it.
And here's the part worth remembering on a hard day. A meaningful share of coverage denials get overturned on appeal when the evidence lines up with the payer's definition.1 The record you wrote at the time of service is that evidence. Which is exactly why the note matters long before any denial shows up.
Why This Matters More Under the 2027 Timed Codes
If you needed one more reason to tighten this up, it's coming on the calendar. CPT 92507 is being deleted in 2027 and replaced by ten new timed codes, with a base code for the initial 30 minutes and add-on codes for each additional 15 minutes.6
Think about what that changes. Today, 92507 is untimed, so a session bills one unit no matter how long it ran or how you documented the minutes. Under the new codes, billing is time-based, and every minute you bill has to be defensible as skilled and medically necessary, not just logged on a schedule.7 Medical necessity documentation stops being a nice-to-have and becomes the thing that protects your billed units when payer scrutiny rises right alongside the new codes.
So build the habit now, while 92507 is still in effect. Capture your skilled rationale, the functional impairment, and your treatment time in a repeatable way this year, and none of it will feel new when the codes flip on January 1, 2027. If you run a university clinic, this is a real teaching moment too. The students you train in fall 2026 will graduate straight into timed billing, so showing them how to document medical necessity from their first note gives them a head start their peers won't have.
Prove It, Don't Assume It
The whole thing comes down to one idea: medical necessity is proven, not assumed. Skilled language, functional goals, and progress tied back to baseline are how you prove it, on every note, for every payer, every time.
The easiest way to make that automatic is to stop relying on memory at the end of a long day. A documentation template that prompts you for cue level, functional impairment, and clinical rationale makes skilled writing the default instead of something you have to remember.
Want documentation that's built for this? ClinicNote's SOAP notes and customizable templates are designed to capture the detail that medical necessity and timed billing both demand, without adding busywork to your schedule. Get a demo and see how it fits your clinic.
Sources
- https://www.asha.org/practice/reimbursement/medical-necessity-for-audiology-and-slp-services/
- https://www.asha.org/Practice/reimbursement/medicaid/Medicaid-Toolkit-Medical-Necessity/
- https://www.asha.org/practice/reimbursement/medicare/medicare_documentation/
- https://www.asha.org/practice/reimbursement/medicare/examples-of-documentation-of-skilled-and-unskilled-care-for-medicare-beneficiaries/
- https://www.asha.org/practice/reimbursement/medicare/documentation-of-skilled-versus-unskilled-care-for-medicare-beneficiaries/
- https://www.asha.org/practice/reimbursement/coding/new-speech-language-pathology-treatment-codes-replacing-92507/
- https://www.asha.org/practice/reimbursement/coding/timedcodesfaqs/