CPT Code 90791: The Definitive Guide to Psychiatric Diagnostic Evaluations
If you're a therapist, LCSW, LPC, LMFT, or psychiatrist who has ever stared at a superbill wondering whether to bill 90791 or 90792 — or gotten a denial on an intake you were certain was documented correctly — this guide is for you.
CPT code 90791 is one of the most important codes in behavioral health billing. It's the gateway code: the first billable encounter with a new client, the foundation of the entire treatment relationship, and unfortunately, one of the most frequently miscoded or under-documented services in mental health practice.
Let's fix that. Here's everything you need to know about 90791 — from what it actually covers to how to document it in a way that survives an audit.
What Is CPT Code 90791?
CPT code 90791 is defined by the American Medical Association (AMA) as a Psychiatric Diagnostic Evaluation — a comprehensive clinical assessment conducted to evaluate a patient's mental health status, history, and treatment needs. It's typically the first service you provide to a new client before initiating any ongoing therapy or medication management.
The key word here is diagnostic. This isn't a getting-to-know-you session or a loose intake conversation. It's a structured clinical evaluation that results in a documented clinical impression and a plan for care.
The full AMA descriptor reads:
"Psychiatric diagnostic evaluation; without medical services."
That phrase — "without medical services" — is what distinguishes 90791 from its sibling code, 90792, which includes medical services such as prescribing evaluation, physical examination components, or ordering labs. More on that distinction in a moment.
Who Can Bill CPT Code 90791?
90791 can be billed by a broad range of behavioral health providers, including:
- Licensed Professional Counselors (LPCs)
- Licensed Clinical Social Workers (LCSWs)
- Licensed Marriage and Family Therapists (LMFTs)
- Psychologists (PhD/PsyD)
- Psychiatrists (MD/DO) — though they more commonly bill 90792
- Psychiatric Nurse Practitioners (PMHNPs) — when not prescribing at the visit
Important: Whether a specific payer reimburses all of these provider types for 90791 varies widely. Medicaid state plans in particular have strict rules about which licensed provider types are covered. Always verify credentialing and covered provider types with each payer before billing.
90791 vs. 90792: What's the Actual Difference?
This is the question we get most often, and it matters — both clinically and financially.
| Feature | CPT 90791 | CPT 90792 |
|---|---|---|
| Full Name | Psychiatric Diagnostic Evaluation | Psychiatric Diagnostic Evaluation with Medical Services |
| Medical Services Included | ❌ No | ✅ Yes |
| Who Typically Bills | Therapists, LCSWs, LPCs, LMFTs, Psychologists | Psychiatrists, PMHNPs |
| Prescribing Component | Not included | Included |
| Physical Exam Component | Not included | May be included |
| 2026 Medicare National Rate (non-facility) | ~$168–$185 | ~$230–$260 |
| Documentation Complexity | Moderate | High |
| Can be billed same day as E/M codes | Generally no | Depends on payer |
The bottom line: if you're a non-prescribing therapist, you will almost always bill 90791. If you're a psychiatrist or PMHNP conducting an evaluation that includes medication discussion, prescribing, or physical assessment, 90792 is likely the right code.
2026 Reimbursement Rates for CPT 90791
Reimbursement for 90791 varies by payer, geographic location, and provider type. Here's a general snapshot of what you can expect:
- Medicare (non-facility, national average): ~$168–$185 per unit
- Medicaid: Highly variable by state; can range from $85 to $165
- Aetna: Typically 100–130% of Medicare rates, depending on contract
- Cigna: Varies by region; generally competitive with Medicare
- BlueCross BlueShield: Varies significantly by BCBS affiliate/state plan
- United Healthcare/Optum: Rates depend on network tier and contract
Pro tip: Always check your specific payer fee schedules through your provider portal. Don't rely on national averages to set your financial expectations — especially for Medicaid, where state-to-state variation is enormous.
What Must Be Documented for CPT 90791?
This is where practices get into trouble. Payers — including Medicare — have specific expectations for what a psychiatric diagnostic evaluation must contain to be medically necessary and billable. Missing elements are the #1 cause of claim denials and audit recoupments.
Here's what your 90791 documentation should include:
1. Chief Complaint and Reason for Referral
Why is this person here? Document the presenting problem in their words or the referring provider's language.
2. History of Present Illness (HPI)
A narrative describing the onset, duration, severity, and context of the current symptoms. Don't skip this — it's the clinical spine of the note.
3. Psychiatric History
Prior diagnoses, hospitalizations, outpatient treatment episodes, previous providers, and treatment response.
4. Medical History
Current medical conditions, medications, allergies. Even if you're not prescribing, payers expect you to document relevant medical context.
5. Family History
Psychiatric and medical family history relevant to the presenting concerns.
6. Social and Developmental History
Current living situation, relationships, employment, trauma history, substance use, legal history — contextualize the person, not just the diagnosis.
7. Mental Status Examination (MSE)
This is non-negotiable. Your MSE should document at minimum:
- Appearance and behavior
- Speech
- Mood and affect
- Thought process and content
- Perceptual disturbances (hallucinations, illusions)
- Cognition and orientation
- Insight and judgment
8. Risk Assessment
Suicidal ideation, homicidal ideation, self-harm history, protective factors. Document this explicitly — "no SI/HI" alone is not sufficient. Document what you assessed and why you concluded what you did.
9. Diagnostic Impression
This is a requirement, not optional. You need at least a preliminary DSM-5-TR or ICD-10-CM diagnosis. Codes like F32.1 (Major Depressive Disorder, moderate) or F41.1 (Generalized Anxiety Disorder) should appear in both your note and your claim.
10. Treatment Recommendations / Plan
What are you recommending? Individual therapy? A medication evaluation referral? A higher level of care? The plan should directly follow from the diagnostic impression.
Common Reasons CPT 90791 Claims Get Denied
Denials on 90791 are frustrating — especially when you've done the clinical work. Here are the most common reasons payers kick these claims back:
❌ Missing or Incomplete Mental Status Examination
Payers audit MSEs carefully. "MSE within normal limits" without any supporting documentation is a red flag and a common audit target.
❌ Diagnosis Code Mismatch
The ICD-10 code on the claim doesn't match what's documented in the note, or you've submitted an unspecified code (e.g., F39) when the documentation supports a more specific diagnosis.
❌ Billing 90791 for an Established Patient
90791 is an evaluation code, not a therapy code. Most payers expect it to be billed once per episode of care — or at the start of a new episode. Billing it annually as a "re-evaluation" without clear documentation of a new episode or new presenting problem will trigger denial.
❌ Concurrent Billing with Therapy Codes
Billing 90791 on the same date as 90837 (individual therapy, 53+ minutes) or other therapy CPT codes typically results in a denial. The diagnostic evaluation stands alone.
❌ No Documented Treatment Plan
Payers expect the evaluation to culminate in a plan. Notes that read as open-ended intake conversations without recommendations are vulnerable.
❌ Credentialing Issues
The provider who rendered the service isn't credentialed with the payer under the NPI billed, or the service was rendered under an unlicensed supervisee without proper incident-to billing documentation.
90791 and Telehealth: What You Need to Know
Since the COVID-19 Public Health Emergency, telehealth billing for behavioral health has expanded significantly, and 90791 is fully eligible for telehealth delivery under most payer policies — including Medicare.
Key billing considerations for telehealth 90791:
- Place of Service Code: Use POS 02 (telehealth, patient not in their home) or POS 10 (telehealth, patient in their home) — not POS 11 (office)
- Modifier 95: Required by many commercial payers for synchronous audio-video telehealth
- GT Modifier: Still required by some Medicaid state plans
- Audio-only: Some payers still reimburse audio-only 90791, but this is narrowing. Always verify with the specific payer.
Medicare's expanded telehealth flexibilities for behavioral health are now permanent under the Consolidated Appropriations Act, which means you can bill 90791 via telehealth without geographic restrictions — a huge win for rural and underserved populations.
Supervision and Incident-To Billing for 90791
If you supervise pre-licensed clinicians, pay attention here.
Incident-to billing under Medicare allows services rendered by non-physicians to be billed under the supervising provider's NPI — but psychiatric diagnostic evaluations (90791) have specific restrictions:
- The supervising physician or NPP must be present in the same suite or office (direct supervision for incident-to, not just general supervision)
- 90791 cannot generally be billed incident-to under Medicare when the supervisee has never met the patient before, unless the supervising provider establishes the plan of care
For commercial payers, incident-to rules vary enormously. Some allow it, some require the rendering provider to be credentialed independently. Never assume — get it in writing from the payer.
State Medicaid programs often have their own supervision billing rules that may be more restrictive than commercial payers.
Audit Defense: How to Protect Your 90791 Claims
Medicare and commercial payers do conduct retrospective audits on behavioral health claims, and 90791 is often on their radar because it's a higher-reimbursing code billed frequently. Here's how to audit-proof your documentation:
- Use a structured template that prompts you to document every required element of the psychiatric evaluation — don't rely on memory
- Be specific in your MSE — document what you observed, not just "normal"
- Link your diagnosis to your symptoms — the note should make it obvious why the patient meets criteria for the diagnosis billed
- Document time when relevant — while 90791 is not a time-based code, documenting the duration of the evaluation adds clinical defensibility
- Ensure your treatment plan is individualized — generic plans ("will attend weekly therapy") are audit vulnerabilities
- Keep records for at least 7 years — or longer per your state's requirements
How Mozu Health Helps You Bill 90791 Correctly
Here's the reality: most denials and audit vulnerabilities for 90791 aren't due to clinical errors. They're documentation errors — rushed notes, missing MSE components, vague treatment plans, or diagnosis-code mismatches that happen when you're seeing six clients in a row.
Mozu Health is an AI-powered clinical documentation platform built specifically for behavioral health providers. Here's what it does for your 90791 workflow:
- AI-guided intake documentation that prompts every required clinical element — from HPI to risk assessment — so nothing gets missed
- Automatic ICD-10 code suggestions aligned to your documented symptoms and clinical impression, reducing diagnosis-claim mismatches
- MSE templates built for psychiatric diagnostic evaluations, not copy-pasted from medical records software
- HIPAA-compliant note storage with audit trail and easy retrieval if you receive a records request
- Billing compliance checks that flag common 90791 errors before the claim goes out
Mozu Health was built by people who understand behavioral health billing — not just EHR developers who bolted on a therapy module. The difference shows in the details.
Frequently Asked Questions About CPT Code 90791
Q1: How many times can I bill 90791 per patient per year?
Most payers allow 90791 to be billed once per episode of care. Some payers allow it to be billed again when a patient returns after a significant gap (e.g., 12+ months) or presents with a substantially new clinical problem. Always check your payer's specific policy — billing it multiple times per year without documentation of a new episode is a common audit trigger.
Q2: Can I bill 90791 and 90837 on the same day?
Generally, no. Most payers — including Medicare — do not allow 90791 (psychiatric diagnostic evaluation) to be billed on the same date as individual psychotherapy codes like 90837, 90834, or 90832. The evaluation code is expected to stand alone. If you did conduct both an evaluation and therapy in the same session, document it carefully and check your payer's specific rules before submitting both.
Q3: What ICD-10 codes can I use with 90791?
Any DSM-5-TR-aligned ICD-10-CM mental health diagnosis is appropriate — provided it's supported by your documentation. Common codes include F32.1 (MDD, moderate), F41.1 (GAD), F43.10 (PTSD, unspecified), F90.2 (ADHD, combined), and F31.81 (Bipolar II). You can also use Z codes (Z03.89, Z13.89) for evaluations where a diagnosis is deferred, but note that some payers require an active psychiatric diagnosis for reimbursement.
Q4: Is 90791 covered by Medicare for telehealth?
Yes. Following permanent telehealth expansions under the Consolidated Appropriations Act, Medicare reimburses 90791 delivered via synchronous audio-video telehealth without geographic restrictions. Use POS 02 or POS 10 depending on the patient's location. Audio-only reimbursement under Medicare for 90791 has more limited — and evolving — coverage, so verify before billing.
Q5: What's the difference between a 90791 and a psychological evaluation (96130/96131)?
Great question. CPT 90791 is a psychiatric diagnostic evaluation focused on clinical interview, history-taking, mental status examination, and diagnostic formulation. CPT codes 96130–96136 are psychological and neuropsychological testing codes that involve standardized psychometric instruments, scored assessments, and formal test interpretation. They serve different clinical purposes and are billed under different circumstances. A psychologist who conducts only a clinical interview without formal testing would bill 90791; one who administers a full battery of standardized instruments would bill the 96130 series.
Q6: Can an LMFT bill 90791?
Yes — in most states and with most payers, LMFTs can bill 90791, provided they are credentialed with the payer and the service is within their scope of practice. However, some state Medicaid plans restrict 90791 billing to certain licensed provider types. Verify your specific payer contracts and state Medicaid provider manual before assuming coverage.
Final Thoughts
CPT code 90791 isn't complicated — but it demands precision. The difference between a clean claim and a denial often comes down to documentation discipline: whether your MSE is specific enough, whether your diagnosis maps to your symptoms, whether your treatment plan is individualized.
Get those elements right consistently, and 90791 is a reliable, high-value code that accurately reflects the critical clinical work you do at the start of every therapeutic relationship.
If you want a documentation system that makes that precision automatic — without adding time to your clinical day — Mozu Health was built for exactly that.
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