CPT Code 90791: Diagnostic Evaluation Billing (2026)

• CPT Codes
• 90791

CPT Code 90791: Diagnostic Evaluation Billing (2026)

90791 billing guide — 2026 rates, 90791 vs 90792, frequency and authorization rules, and how facilities bill intakes (including H-code states).

Quick Reference

Code

90791

Code System

CPT

Category

CPT Codes

Published

Mar 4, 2026

Updated

Jun 11, 2026

Reading Time

13 min

CPT® is a registered trademark of the American Medical Association. All CPT code descriptions on this page are paraphrased in original wording; consult the current CPT® codebook published by the AMA for authoritative descriptors.

CPT Code 90791: Psychiatric Diagnostic Evaluation

CPT 90791 is the psychiatric diagnostic evaluation — the comprehensive intake assessment of a patient’s psychiatric history, mental status, and current presentation, performed without medical services (no physical exam or prescribing component). It is an untimed code: what qualifies the encounter is completing and documenting the full evaluation, not hitting a minute threshold, though most evaluations run 45–90 minutes. At behavioral health facilities this is the admission code — every census admit generates a 90791 (or a state H-code equivalent, covered below), which makes it the anchor of the intake billing workflow.

Does 90791 Require Prior Authorization?

Often not for the initial evaluation — many commercial plans and Medicaid programs allow the first diagnostic evaluation without prior authorization, treating it as the gateway service that generates the authorization for everything after it. But this is payer-specific: some managed care plans require auth even for intake, and re-evaluations after the first are more commonly gated. Verify per payer during the verification-of-benefits call, and document the reference number when auth is required. See prior authorization for how the process works.

Does 90791 Pay More Than a Therapy Session?

Yes. Medicare prices 90791 above 90834 and above 90837, reflecting the comprehensive scope of a diagnostic evaluation versus a psychotherapy session, and 90792 pays more still because it includes medical services. In 2026 national non-facility terms: 90791 at $173.35 vs $167.00 for 90837 and $113.90 for 90834, with 90792 at $202.08.

Medicare National Non-Facility Rates by Year

Rates reviewed: June 2026.

Rates are national non-facility amounts; locality adjustments apply, and commercial contracts set their own fees — do not quote Medicare figures to project commercial revenue.

How Often Can 90791 Be Billed?

The working norm: once per provider per patient per episode of care, with a re-evaluation justified by a meaningful clinical change — a gap in care, a new episode, a level-of-care change, or a significant shift in presentation. Beyond that, policy genuinely varies: some payers cap diagnostic evaluations annually, some Medicare Administrative Contractors publish LCD frequency guidance, and Medicaid programs set their own limits. There is no single national frequency rule, and any page that asserts one is glossing. Check the MAC’s LCD and the payer manual for each major contract, and build those limits into your charge review.

Who Can Bill 90791?

Psychiatrists, psychologists, LCSWs, LPCs, LMFTs, and other licensed mental health professionals within state scope-of-practice and payer credentialing rules. The distinction from 90792 is the medical-services component: 90792 requires a clinician authorized to perform medical services (MD/DO, and NP/PA per state law). Non-prescribing clinicians always use 90791. Medicare additionally limits which non-physician specialties it enrolls and pays directly — confirm credentialing before the intake schedule assumes billability.

90791 vs 90792

At facilities both commonly occur for one admission: the therapist completes the 90791 biopsychosocial evaluation, and the psychiatrist separately completes a 90792 with medication assessment. Same-episode billing of both by different providers is widely payable; same-day stacking is subject to payer rules and NCCI edits — sequence them on different days where the payer is restrictive.

Add-On and Adjacent Codes

• 90785 interactive complexity — when communication barriers (e.g., a third party, play equipment for a child) complicate the evaluation.
• Psychological/neuropsychological testing ( 96130, 96136 families) — when intake includes formal testing, billed under the testing codes, not stretched into the eval.
• Crisis codes — if the intake becomes a crisis encounter, 90839 may be the correct code for that day instead of 90791; the same clinician should not bill both same-day.

90791 at Facility Intake: The H-Code Question

The section solo-practice guides never write: many state Medicaid programs and Medicaid managed-care contracts do not want 90791 for facility intakes. They require HCPCS assessment codes instead — H0001 (alcohol and/or drug assessment) for SUD admissions, H0031 (mental health assessment by non-physician) for MH admissions.

Working decision guidance by payer type:

The pattern is concrete at the state level: several state Medicaid programs require H0001 for the SUD intake assessment in licensed treatment programs and reserve 90791 for outpatient mental health settings or specific provider types, while others pay 90791 across the board and use H0031 only for non-physician MH assessments in community programs. The same state can split the answer by delivery system: fee-for-service follows the published fee schedule, while each Medicaid MCO’s provider manual can override it. The only durable rule is the unglamorous one — pull the current fee schedule and the MCO manual for every Medicaid contract you admit under, and re-check at contract renewal.

Billing 90791 to an H-code state Medicaid program (or vice versa) is a clean denial that delays the entire admission’s revenue, because the eval anchors the authorization. Map the intake code per payer in your charge logic, not in the clinician’s head.

• Commercial plans — almost always 90791/90792.
• Medicare — 90791/90792 (H-codes are not Medicare codes).
• Medicaid fee-for-service and MCOs — check the state behavioral health fee schedule and the specific MCO contract; SUD programs frequently bill H0001 for intake assessment, MH programs H0031, with 90791 reserved for specific provider types or settings.

Intake Workflow Compliance at Scale

• Same-day first therapy session: under NCCI edits, the diagnostic evaluation is generally not separately payable on the same day as psychotherapy by the same provider — schedule the first therapy session on a different day, or expect the bundled denial.
• The documentation package is the authorization’s foundation: utilization review anchors the initial authorization — level of care, length of stay, and continued-stay reviews — to the 90791 evaluation. A thin eval costs more than one claim; it weakens every subsequent auth request for the episode.
• One admit, multiple billables: a typical facility admission can generate a 90791 (therapist), a 90792 (psychiatrist), and required state assessments — sequence and document them as distinct services to survive audit.

Worked Example: One Admission, Day by Day

A fictional sequence shows how the pieces order themselves. “Riley” is admitted to a residential SUD program on a commercial PPO on Monday:

Two scheduling decisions in that sequence — psychiatrist on day two, therapy on day three — exist purely to keep three billable services from colliding. Facilities that let intake scheduling run ahead of billing logic generate the same denials every admission week; the fix is a standing intake template per payer, not per-claim cleanup.

• Monday (admission day): the VOB confirms the diagnostic evaluation needs no prior auth and the payer wants 90791 (not an H-code). The primary therapist completes the 90791 — full biopsychosocial, MSE, substance use history, DSM-5-TR diagnosis, initial treatment plan. The UR coordinator submits the initial authorization request the same day, built on that eval.
• Tuesday: the psychiatrist completes the 90792 — psychiatric evaluation with medical services, medication history, and induction decisions. Different provider, different documented service, separate claim line; scheduled a day after the 90791 because this payer bundles same-day evals.
• Wednesday: first individual therapy session ( 90834 ) — deliberately not scheduled on Monday, because the same-provider same-day eval+psychotherapy pair generally bundles under NCCI.
• Day 5–7: the authorization comes back keyed to the 90791’s level-of-care justification; continued-stay reviews for the rest of the episode will cite the eval’s baseline MSE and severity documentation.

Documentation Requirements

Each element of the evaluation maps to a downstream use — document with that in mind:

The cost of a thin eval is rarely the 90791 claim itself — it is everything downstream. The initial authorization, every continued-stay review, and the defense of every subsequent claim in the episode trace back to this one document. Facilities that audit their own intake documentation find the same pattern payers do: episodes anchored to skeletal evals get shorter authorizations, more peer reviews, and earlier denials. Treat the 90791 note as the episode’s load-bearing wall, and give clinicians a template that makes the complete version the easy version.

• Chief complaint and history of present illness → establishes medical necessity for the episode. The HPI should capture acuity in concrete terms — frequency and recency of use or symptoms, functional impairment, failed lower levels of care — because those are the phrases UR will quote back to the payer.
• Psychiatric history, substance use history, medical history → supports level-of-care placement criteria. For SUD admissions, structure the substance history so it maps onto the placement-criteria dimensions the payer uses ( withdrawal risk, biomedical conditions, relapse history, recovery environment); an eval organized that way pre-writes the auth request.
• Mental status examination → baseline for continued-stay reviews. Every later “patient improving/not improving” argument is measured against this MSE — vague baselines (“mood okay, affect appropriate”) make continued-stay cases harder to win.
• Biopsychosocial assessment → required by most state licensure rules and accreditation standards for facility admissions. It is also where social determinants land — housing instability, legal involvement, family system — which both justify level of care and feed discharge planning.
• Diagnosis (DSM-5-TR/ICD-10-CM) → drives the claim and the authorization. Code to the documented severity and specifiers; an unspecified diagnosis at intake invites a records request on the very first claim of the episode.
• Initial treatment plan and disposition → what UR cites when requesting authorized days/sessions. The plan should name modalities, frequency, and measurable goals — “individual therapy 2x/week targeting relapse prevention” authorizes; “continue treatment” does not.

Telehealth

90791 has been payable via telehealth, with place-of-service 02 (telehealth, patient not at home) or 10 (patient at home) and modifier 95; audio-only allowances have shifted year to year and by payer. Confirm 90791’s status — and any audio-only flag — on the current CMS telehealth services list before standing up remote intake workflows.

Remote intake is operationally attractive — it fills beds faster by evaluating patients before they travel — but it adds three checks to the workflow: the evaluating clinician must be licensed in the state where the patient is located at the time of the eval (interstate compacts help for psychology but not uniformly across license types); the payer must cover a telehealth diagnostic evaluation, not just telehealth therapy; and identity/location verification belongs in the note. A 90791 performed across a state line by a clinician unlicensed in the patient’s state is not a billing error — it is unlicensed practice, and no modifier fixes it.

Common Modifiers

Modifier 95 (or 93 where audio-only is permitted) for telehealth; state Medicaid credential modifiers (e.g., AJ, HO) where the fee schedule requires licensure-level reporting. No time-based modifiers apply — the code is untimed.

Compliance Considerations

Audit exposure for 90791 concentrates in frequency (re-evaluations without documented clinical justification), same-day stacking with psychotherapy, and evaluations whose documentation doesn’t contain the full diagnostic elements. Facilities should sample intake claims quarterly and reconcile the intake-code map (90791 vs 90792 vs H-codes) against current payer contracts every renewal cycle.

Every admission is an intake eval, a VOB, an authorization, and a claim — run them as one workflow. See how ’s CRM handles admissions and how the RCM platform takes the eval from documentation to paid claim, or request a demo. runs automated, real-time eligibility verification via 270/271 EDI at intake.

Related Billing Codes

• 90785
• 90792
• 90832
• 90833

Reference tables

Common questions

Official sources

No publisher link is recorded for this topic yet. Confirm the requirement with the governing payer, state agency or accreditor before relying on it — see the primary source directory.