The intake session is the first claim every new client generates, and 90791 is the code that carries it. Get it wrong and payment on the whole episode of care stalls before treatment even starts. Yet the rules around this code confuse experienced billers: how often you can report it, whether it can share a date with therapy, and what documentation an auditor actually wants to see.
This guide walks through 90791 for behavioral health practices. You’ll learn what the code covers, who can bill it, the documentation payers expect, the frequency and same-day rules, how 90791 vs 90792 differ, and the denials that catch practices off guard.
What the 90791 CPT Code Actually Covers
90791 is the psychiatric diagnostic evaluation without medical services. Think of it as the integrated biopsychosocial assessment you complete when a client first walks in the door. It captures the story, the symptoms, and the plan.
A complete evaluation under this code includes a psychiatric history, a mental status exam, a diagnostic impression, and treatment recommendations.1 The work is clinical assessment, not medical management.
Here’s the boundary that matters: the 90791 cpt code excludes medical services. No prescribing, no physical exam tied to medication decisions, no evaluation and management component. The moment a medical assessment enters the picture, you’re looking at 90792 instead.2
One historical note that still trips people up: 90791 replaced the old 90801 intake code years ago. If your templates or cheat sheets still reference 90801, they’re out of date.
Who Can Bill 90791
Good news for most behavioral health teams: 90791 is open to a wide range of licensed clinicians. Psychologists, licensed clinical social workers, licensed professional counselors, and marriage and family therapists can all bill it. So can psychiatrists and psychiatric nurse practitioners.3
That breadth is exactly why the code gets misapplied. A prescriber who performs a medical assessment during intake should usually reach for 90792, not 90791. And a non-prescriber can never bill 90792, because it requires medical services they aren’t licensed to deliver.
State scope-of-practice laws and each payer’s credentialing rules still set the outer limits. A solo LCSW in Asheville is squarely eligible to bill 90791 for a new client. A psychiatric mental health nurse practitioner doing the same intake, while also reviewing medications, belongs in 90792 territory. Match the code to the work and the credential, not to habit.
90791 Documentation Requirements
Thin intake notes are the fastest way to lose an intake claim in an audit. Payers expect the evaluation to show its work.
At minimum, your documentation should capture a complete medical and psychiatric history, including past, family, and social history, along with a mental status exam, a diagnosis, and treatment recommendations.1 These are the bones of a defensible intake note.
A few requirements catch practices by surprise:
- The client generally must be present. If only a parent or partner attends and the patient isn’t there, 90791 usually can’t be billed for that encounter.
- When communication factors complicate the evaluation, such as a caregiver acting as an interpreter of the patient’s behavior, the interactive complexity add-on 90785 may apply.4
This is where behavioral health-specific tools earn their keep. PIMSY ships with intake templates and a custom note builder that prompt for each required element, so the history, mental status exam, and diagnosis land in the record the first time. When the documentation is structured, mental health documentation software stops being a compliance risk and starts being a safeguard.
Time and Frequency: How Often Can You Bill 90791
Start with what 90791 is not: a time-based code. There’s no minute threshold that determines whether you can report it, unlike the E/M codes prescribers use. You bill it because you completed the evaluation, not because you hit a clock.
Frequency is where the denials pile up. Many payers, including Medicare and Medicaid plans, allow the code roughly once per client per provider per episode of care.3 Submit a second intake for the same client and provider too soon, and expect a duplicate denial.
Some payers do permit a repeat evaluation, for instance when a client returns after a long gap and opens a new episode, or when a different provider conducts a separate assessment. Check the specific payer policy before you assume.
Then there’s the same-day rule. As a general matter, you can’t bill this evaluation alongside a psychotherapy code or an E/M service by the same provider on the same date.2 The intake and the first therapy session usually need to live on different days, or under different providers, to both get paid.
90791 vs 90792: Choosing the Right Evaluation Code
The cleanest way to keep these straight: 90791 is the evaluation without medical services, and 90792 is the same evaluation with medical services.2
Non-prescribers use 90791. Prescribers who assess medical status, review or adjust medications, or factor physical health into the diagnostic picture use 90792. The clinical work drives the choice.
Reimbursement follows the work, too. 90792 typically pays more than 90791 because it bundles a medical assessment on top of the diagnostic evaluation.2 That gap is why an accurate call protects revenue in both directions: a prescriber who defaults to 90791 leaves money on the table, and a non-prescriber who bills 90792 invites a denial or a clawback. If your team includes both therapists and prescribers, see our companion guide on 90792 for the prescriber side of this decision.
Common 90791 Denials and How to Prevent Them
Most 90791 denials trace back to a short list of causes: a duplicate that breaks the frequency rule, a same-day conflict with therapy or an E/M visit, the wrong provider type for the code, documentation that’s too thin, or a session where the patient wasn’t present.
The fix is catching these before the claim leaves your office, not after the remittance comes back. Real-time eligibility checks confirm coverage up front. Claim scrubbing flags conflicts and missing elements while you can still correct them.
PIMSY handles this inside the same workflow where you document. Electronic claims submission, real-time eligibility, and clearinghouse integrations work together so an intake claim goes out clean. When your behavioral health billing software understands these coding rules, denials stop being a monthly surprise and start being rare.
Conclusion: Get Intake Coding Right the First Time
Accurate 90791 coding protects the first claim of every new client relationship, and a clean intake sets the tone for the whole episode of care. The rules aren’t complicated once you separate them: know what the code covers, match it to the right credential, document the full evaluation, respect the frequency and same-day limits, and choose 90791 or 90792 based on the medical work involved.
PIMSY was built for behavioral health, with intake templates, a flexible note builder, and billing tools that keep these coding rules front and center. Ready to see how much smoother your intake billing can run? Book a demo and we’ll walk through your workflow together.
Sources
1 AAPC, Documentation Requirements for CPT Code 90791
2 CMS, Billing and Coding: Psychiatric Diagnostic Evaluation and Psychotherapy Services
3 American Psychological Association, Psychiatric Diagnostic Evaluation Coding and Reimbursement
