CPT code 90791 is the billing code for psychiatric diagnostic evaluations performed without medical services. If you conduct intake assessments, comprehensive evaluations, or diagnostic interviews as an LMHC, LCSW, LMFT, or psychologist, this is likely your primary intake billing code.
This guide covers everything you need to know about 90791: what it includes, documentation requirements, common billing mistakes, and how it differs from other evaluation codes.
What is CPT Code 90791?
CPT 90791 describes a psychiatric diagnostic evaluation that includes:
- History of present illness and chief complaint
- Psychiatric and mental health history
- Personal and family history relevant to the diagnosis
- Medical history review (without physical examination)
- Mental status examination
- Communication with family or other sources (when appropriate)
- Diagnostic formulation and treatment recommendations
The evaluation establishes the foundation for treatment planning and provides the diagnostic basis for ongoing psychotherapy services.
90791 vs 90792: Understanding the Difference
The distinction is straightforward:
90791 — Psychiatric Diagnostic Evaluation
Used by non-prescribing clinicians (LMHCs, LCSWs, LMFTs, psychologists). No physical examination or medication management included.
90792 — Psychiatric Diagnostic Evaluation with Medical Services
Used by prescribers (psychiatrists, psychiatric NPs, some PAs). Includes physical examination, vital signs, and/or medication evaluation as part of the assessment.
If you cannot prescribe medication, you will always use 90791.
Time Requirements for 90791
Unlike psychotherapy codes (90832, 90834, 90837), CPT 90791 is not time-based. The code covers the complete diagnostic evaluation regardless of how long it takes.
That said, most thorough psychiatric evaluations take 60-90 minutes. Evaluations significantly shorter than 45 minutes may prompt payer review, as auditors question whether a comprehensive assessment was actually performed.
Document your actual time, but focus on the completeness of your evaluation rather than hitting a specific duration.
Documentation Requirements
Your 90791 documentation should include all of the following components:
Identifying Information
Client demographics, referral source, reason for evaluation
Chief Complaint
The client's primary concerns in their own words when possible
History of Present Illness
Current symptoms, onset, duration, severity, precipitating factors, and impact on functioning
Psychiatric History
Previous diagnoses, treatment history, hospitalizations, medication trials, previous providers
Medical History
Relevant medical conditions, current medications, allergies, recent physical exam findings
Family History
Psychiatric conditions in first-degree relatives, family medical history relevant to presentation
Social and Developmental History
Education, employment, relationships, living situation, substance use, trauma history, developmental milestones if relevant
Mental Status Examination
Appearance, behavior, speech, mood, affect, thought process, thought content, perceptions, cognition, insight, judgment
Risk Assessment
Suicidal ideation, homicidal ideation, self-harm, safety planning if indicated
Diagnostic Impressions
ICD-10 diagnosis codes with clinical justification. Link your findings to your diagnostic conclusions.
Treatment Recommendations
Recommended frequency and modality of treatment, referrals, and initial treatment goals
Billing 90791: Common Scenarios
Initial Intake with New Client
This is the most common use. Bill 90791 for your first session when conducting a comprehensive diagnostic evaluation.
Re-evaluation After Extended Break
If a client returns after 12+ months and their clinical picture may have changed, a new 90791 may be appropriate. Document why a new comprehensive evaluation was clinically indicated.
Significant Change in Presentation
If a client develops new symptoms suggesting a different or additional diagnosis, you may bill 90791 for the evaluation. Document the clinical change that necessitated re-evaluation.
Transfer from Another Provider
When a client transfers to your care, you should conduct your own diagnostic evaluation. Bill 90791 even if the client has a recent evaluation elsewhere.
What 90791 Does Not Include
90791 covers the evaluation only. It does not include:
- Psychological or neuropsychological testing (use 96130-96139 series)
- Ongoing psychotherapy (use 90832, 90834, 90837)
- Therapy provided in the same session as the evaluation
- Physical examination or medication prescribing (that's 90792)
- Interactive complexity add-on (that's 90785, and it can be added to 90791)
Can You Bill 90791 with Other Codes?
90791 + 90785 (Interactive Complexity)
Yes. Add 90785 when the evaluation involves communication with third parties, use of play equipment or interpreters, or when the client's emotional state significantly complicates the evaluation.
90791 + Psychotherapy Codes (90832, 90834, 90837)
Generally no. Most payers bundle these. The diagnostic evaluation is expected to include therapeutic communication. Check specific payer policies before billing both.
90791 + Crisis Codes
Context-dependent. If you conduct an evaluation and the client enters crisis requiring intervention, document both services clearly and check payer bundling rules.
Reimbursement Rates for 90791
Reimbursement varies by payer and region. As a general reference:
| Payer Type | Typical Range |
|---|---|
| Medicare | $150 - $180 |
| Medicaid | $80 - $150 (varies by state) |
| Commercial Insurance | $150 - $250 |
| Private Pay | $175 - $350 |
These are approximations. Verify rates with your specific payers and contracts.
Common 90791 Billing Mistakes
Billing 90791 for Brief Screenings
A 20-minute intake call is not a psychiatric diagnostic evaluation. If you're not conducting a comprehensive assessment, use a psychotherapy code or don't bill.
Using 90791 for Medication Checks
If you're a prescriber doing a medication-focused evaluation, use 90792. Non-prescribers cannot bill 90792.
Routine Re-billing Without Clinical Justification
Billing 90791 annually without documenting why a new comprehensive evaluation was needed invites audit problems.
Missing Required Documentation Elements
Payers can recoup payments if your documentation doesn't support a comprehensive evaluation. Include all required components.
Forgetting the ICD-10 Code
90791 establishes the diagnosis. Always include at least one ICD-10 diagnostic code with your claim. See our ICD-10 codes guide for common diagnoses.
Frequently Asked Questions
- What is the difference between 90791 and 90792?
- CPT code 90791 is for psychiatric diagnostic evaluations without medical services, typically used by non-prescribing clinicians like LMHCs, LCSWs, and psychologists. CPT 90792 includes medical services and is used by psychiatrists and other prescribers who perform physical examinations or medication management as part of the evaluation.
- How long should a 90791 evaluation take?
- While 90791 is not time-based, most comprehensive psychiatric diagnostic evaluations take 60-90 minutes. The code covers the full evaluation regardless of duration, but your documentation should reflect a thorough assessment. Sessions under 45 minutes may raise payer scrutiny.
- Can I bill 90791 and 90834 on the same day?
- Generally no. Most payers consider 90791 and psychotherapy codes (90832, 90834, 90837) mutually exclusive on the same date of service. The diagnostic evaluation is expected to encompass therapeutic elements. However, some payers allow it with modifier 59 if the services are clearly distinct. Check your specific payer policies.
- How often can I bill 90791 for the same client?
- 90791 is typically billed once at the start of treatment. You can bill it again if there's a significant change in the client's condition requiring a new comprehensive evaluation, or if a substantial time gap (usually 12+ months) has passed since the last evaluation. Document the clinical rationale for any repeat evaluations.
- What documentation is required for 90791?
- Documentation should include: chief complaint and presenting problems, psychiatric history, medical history, family history, social and developmental history, mental status examination, risk assessment, diagnostic impressions with ICD-10 codes, and initial treatment recommendations. The note should demonstrate medical necessity for treatment.
90791 is your intake code—use it for comprehensive diagnostic evaluations that establish the clinical foundation for treatment. Document thoroughly, include all required elements, and pair with appropriate ICD-10 codes. Accuracy protects your revenue and supports quality care.