CPT code 90791 is the foundation of mental health treatment billing. This psychiatric diagnostic evaluation code covers your initial intake assessment, where you gather comprehensive clinical information, establish diagnoses, and develop treatment recommendations. Getting 90791 billing right sets the stage for accurate ongoing treatment claims and establishes medical necessity for all services that follow.
This comprehensive guide covers everything mental health professionals need to know about CPT 90791: what it includes, how it differs from 90792, documentation requirements, reimbursement expectations, and strategies to prevent denials while maximizing appropriate compensation for your thorough intake work.
What Is CPT 90791?
CPT 90791 represents the psychiatric diagnostic evaluation, an in-depth clinical assessment performed at the beginning of treatment or when a comprehensive re-evaluation is clinically warranted. The American Medical Association defines this code as:
"Psychiatric diagnostic evaluation."
This code describes a comprehensive evaluation that includes history, mental status examination, and communication with family or other sources when appropriate, along with ordering and interpretation of diagnostic studies when needed.
Unlike time-based psychotherapy codes (90832, 90834, 90837), CPT 90791 is not strictly time-bound. Instead, it covers the complete diagnostic evaluation process, which typically ranges from 45 to 90 minutes of face-to-face time, plus additional time for collateral contacts, record review, and documentation.
Key Facts About 90791
- Purpose: Comprehensive psychiatric or psychological assessment to establish diagnoses and treatment recommendations
- Timing: Typically billed at initial intake; may be billed for comprehensive re-evaluations when clinically indicated
- Medical Component: Does NOT include medical examination (use 90792 when medical exam is performed)
- Provider Types: Billable by psychiatrists, psychologists, licensed clinical social workers, licensed professional counselors, and other qualified mental health professionals
- Frequency: Generally once per treatment episode; additional evaluations require clear clinical justification
- Interactive Complexity: Add-on code 90785 may be used when specific complexity factors are present
CPT 90791 vs 90792: Understanding the Difference
One of the most common billing questions involves when to use 90791 versus 90792. The distinction is straightforward but critically important for accurate billing.
CPT 90791: Diagnostic Evaluation WITHOUT Medical Services
- Comprehensive psychiatric history
- Mental status examination
- Review of relevant records
- Collateral contacts when appropriate
- Diagnostic formulation
- Treatment recommendations
- No physical examination performed
- Used by non-prescribing clinicians
CPT 90792: Diagnostic Evaluation WITH Medical Services
- Everything included in 90791, PLUS:
- Physical examination components
- Medical decision-making
- Prescription management considerations
- Laboratory ordering and interpretation
- Medical differential diagnosis
- Used primarily by psychiatrists and physicians
- Higher reimbursement rate
Critical Billing Distinction
If you are a psychiatrist or physician and you perform a physical exam, review labs, or engage in medical decision-making as part of your evaluation, you should bill 90792, not 90791. Using 90791 when medical services were provided constitutes undercoding. Conversely, non-prescribing clinicians (psychologists, LCSWs, LPCs) should always use 90791 since they do not provide medical services.
Reimbursement Comparison
| Code | Description | Medicare Rate (2024) | Commercial Range |
|---|---|---|---|
| 90791 | Psychiatric diagnostic evaluation | $150-175 | $175-250 |
| 90792 | Psychiatric diagnostic evaluation with medical services | $185-210 | $200-300 |
Time Expectations and Evaluation Components
While CPT 90791 is not a time-based code, payers and auditors expect the evaluation to be comprehensive enough to justify the service. Here is what a thorough diagnostic evaluation typically includes:
Required Components of a Psychiatric Diagnostic Evaluation
90791 Evaluation Components Checklist
Typical Time Breakdown
Medicare vs Commercial Reimbursement Rates
Reimbursement for 90791 varies based on payer, geographic location, and provider credentials. Understanding these rates helps you assess whether your contracted rates are competitive.
2024-2025 Medicare Rates
Medicare rates for 90791 are determined by the Physician Fee Schedule and vary by geographic locality:
Commercial Insurance Rates
Commercial payers typically reimburse 115-150% of Medicare rates, though this varies significantly by region and contract:
- Blue Cross Blue Shield: $180-240 average
- Aetna: $175-225 average
- United Healthcare: $170-220 average
- Cigna: $165-215 average
- Medicare Advantage: Similar to traditional Medicare
Negotiation Opportunity
Your intake evaluation is one of the most comprehensive services you provide. If your contracted rate for 90791 falls below $175, consider renegotiating. A thorough diagnostic evaluation takes 2-3 hours of total clinician time when you factor in preparation, face-to-face assessment, and documentation. Make sure your compensation reflects this investment.
Required Documentation Elements
Strong documentation is your best defense against claim denials and audit recoupments. For 90791, your evaluation report must demonstrate a comprehensive assessment that justifies the service level billed.
Mental Status Examination Components
Every 90791 evaluation must include a thorough mental status examination. Document each of these elements:
| MSE Component | What to Document |
|---|---|
| Appearance | Grooming, hygiene, dress, apparent age, distinguishing features |
| Behavior | Psychomotor activity, eye contact, cooperation, mannerisms |
| Speech | Rate, rhythm, volume, tone, spontaneity, articulation |
| Mood | Patient's subjective emotional state in their own words |
| Affect | Observed emotional expression, range, congruence with mood |
| Thought Process | Organization, coherence, goal-directedness, associations |
| Thought Content | Delusions, obsessions, phobias, preoccupations, suicidal/homicidal ideation |
| Perceptions | Hallucinations, illusions, depersonalization, derealization |
| Cognition | Orientation, attention, concentration, memory, abstraction |
| Insight | Awareness of illness and need for treatment |
| Judgment | Decision-making capacity, impulse control, reality testing |
Sample Documentation Structure
PSYCHIATRIC DIAGNOSTIC EVALUATION
Chief Complaint: "I have been feeling anxious all the time and cannot sleep."
History of Present Illness: [Detailed narrative of symptom onset, course, severity, and precipitants]
Past Psychiatric History: [Previous diagnoses, treatments, hospitalizations, medication trials]
Substance Use History: [Alcohol, drugs, tobacco, caffeine use patterns]
Medical History: [Relevant conditions, current medications]
Family History: [Psychiatric and substance use disorders in family]
Social History: [Development, education, occupation, relationships, living situation]
Mental Status Examination: [Complete MSE with all components]
Risk Assessment: [Suicidal ideation, homicidal ideation, self-harm, violence risk]
Diagnostic Impression: [DSM-5 diagnoses with supporting rationale]
Treatment Recommendations: [Modality, frequency, goals, referrals]
When Can You Bill CPT 90791?
Understanding when 90791 is appropriate helps you capture revenue for legitimate evaluations while avoiding problematic billing patterns.
Appropriate Uses for 90791
- ✓ Initial intake evaluation for new patients
- ✓ Re-evaluation after significant clinical change
- ✓ Evaluation following treatment gap of 12+ months
- ✓ Comprehensive assessment for new diagnosis
- ✓ Evaluation required by court or agency
- ✓ Second opinion diagnostic consultation
When NOT to Use 90791
- ✗ Routine follow-up sessions (use 90834/90837)
- ✗ Brief reassessments during treatment
- ✗ Treatment planning sessions without full evaluation
- ✗ Medication checks (use E/M codes)
- ✗ Annual reviews without clinical change
- ✗ To bill higher when first session runs long
Frequency Limitations and Re-Evaluation Guidelines
Most payers limit how often you can bill 90791 for the same patient. Understanding these limits prevents claim denials and potential fraud allegations.
General Frequency Guidelines
- Medicare: Typically once per treatment episode; re-evaluation requires documented clinical justification showing substantial change warranting comprehensive reassessment
- Medicaid: Varies by state; many limit to once per year without prior authorization
- Commercial Payers: Generally once per 12-month period; additional evaluations may require prior authorization and clinical documentation
- Managed Care: Often requires authorization for any 90791 beyond the initial intake
When Re-Evaluation Is Justified
Billing a second 90791 for an existing patient requires clear clinical justification. Acceptable scenarios include:
- Patient returns after 12+ months without treatment and presents with new or significantly changed symptoms
- Major life event (trauma, loss, medical diagnosis) fundamentally changes the clinical picture
- Previous diagnoses appear incorrect based on new information or treatment response
- Court-ordered or agency-required reassessment for specific purpose
- Transfer of care requiring comprehensive baseline for new treatment approach
Payer-Specific Rules and Considerations
Each payer has unique requirements for 90791. Being aware of these nuances helps you submit clean claims that get paid on the first submission.
Medicare
Covers 90791 for psychiatrists, psychologists, clinical social workers, and other qualified providers. Documentation must support medical necessity. Telehealth coverage continues post-pandemic with appropriate modifiers. No prior authorization typically required for initial evaluation.
Blue Cross Blue Shield
Most BCBS plans cover 90791 without prior authorization for initial intake. Some plans require the evaluation to be completed within 1-2 sessions. Documentation requirements vary by state plan. Check specific plan guidelines for telehealth coverage.
United Healthcare
Generally covers 90791 for in-network providers. May request clinical documentation if evaluation exceeds typical duration. Optum Behavioral Health manages many UHC mental health benefits with specific network requirements.
Aetna
Covers 90791 for qualified providers. May have separate behavioral health network managed by Aetna Behavioral Health. Prior authorization typically not required for initial evaluation but may be needed for re-evaluations.
Medicaid (State Variations)
Coverage and requirements vary significantly by state. Some states limit to specific provider types or settings. Prior authorization requirements are common. Check your state Medicaid provider manual for specific guidelines.
Common Denial Reasons and Prevention Strategies
Understanding why 90791 claims get denied helps you prevent these issues before they occur. Here are the most common denial reasons and how to avoid them:
Insufficient Documentation
Prevention: Ensure your evaluation includes all required components: comprehensive history, complete MSE, risk assessment, diagnostic formulation, and treatment recommendations. Use structured templates to avoid missing elements.
Frequency Limit Exceeded
Prevention: Check patient history before billing 90791. If billing a re-evaluation, document clear clinical justification showing why a new comprehensive evaluation is warranted. Obtain prior authorization when required.
Medical Necessity Not Established
Prevention: Document presenting symptoms, functional impairment, and why a comprehensive evaluation (versus a standard therapy session) was clinically indicated. Link findings to DSM-5 diagnostic criteria.
Wrong Code Selection
Prevention: Use 90791 only for comprehensive diagnostic evaluations. If you performed a medical exam, use 90792. Do not use 90791 for routine therapy sessions that happen to run long.
Provider Credentialing Issues
Prevention: Verify your credentials allow billing for 90791 with each payer. Ensure your NPI is active and correctly linked to your practice. Update credentialing information promptly when anything changes.
Missing or Incorrect Diagnosis Code
Prevention: Include appropriate ICD-10 diagnosis codes that support the evaluation. Avoid using unspecified codes (ending in .9) when a more specific diagnosis is documented. Ensure the diagnosis supports the need for psychiatric evaluation.
Real-World Billing Scenarios
These scenarios illustrate common situations where 90791 billing questions arise:
Scenario A: Standard New Patient Intake
Situation: A licensed clinical social worker conducts a 75-minute comprehensive intake with a new patient presenting with symptoms of depression and anxiety. The clinician gathers full psychiatric history, completes MSE, assesses risk, establishes DSM-5 diagnoses, and develops treatment recommendations.
Correct Billing: 90791
Key Point: This is the classic use case for 90791. The comprehensive nature of the evaluation, with all required components documented, supports this service level.
Scenario B: Evaluation Split Across Two Sessions
Situation: Due to the patient's complexity, a psychologist conducts the intake evaluation over two 50-minute sessions. The first session covers history gathering; the second completes the MSE, diagnostic formulation, and treatment planning.
Correct Billing: 90791 on the second date of service when the evaluation is complete. The first session can be billed as 90791 if it represents a complete evaluation, or as 90837 if it was primarily psychotherapy/information gathering that is part of the larger evaluation.
Key Point: Some payers allow split evaluations; others require 90791 to be completed in a single session. Check payer guidelines. Document the clinical reason for splitting the evaluation.
Scenario C: Patient Returns After Two-Year Gap
Situation: A patient who completed treatment two years ago returns with new symptoms following a significant life stressor. The therapist conducts a full re-evaluation to assess current presentation and update the treatment plan.
Correct Billing: 90791
Key Point: A comprehensive re-evaluation after a significant treatment gap is appropriate. Document why a new evaluation (versus resuming prior treatment) was clinically indicated. Note the time elapsed and changes in the clinical picture.
Scenario D: Telehealth Intake Evaluation
Situation: A licensed professional counselor conducts a comprehensive diagnostic evaluation via secure video platform with a new patient located at home.
Correct Billing: 90791-95 (or 90791-GT depending on payer) with Place of Service 10 (Telehealth in patient home) or 02 (Telehealth other)
Key Point: Telehealth evaluations are billable with appropriate modifiers. Document that the evaluation was conducted via real-time audio/video. Ensure you comply with state telehealth regulations regarding patient location.
Scenario E: Evaluation with Interactive Complexity
Situation: A psychologist evaluates an adolescent patient. The session requires managing difficult communication with the patient who has a developmental delay, integrating collateral information from parents, and navigating family conflict about treatment.
Correct Billing: 90791 + 90785 (Interactive Complexity add-on)
Key Point: The add-on code 90785 can be used with 90791 when specific complexity factors are present: communication difficulties, third-party involvement, or the need to manage emotional/behavioral dysregulation during the evaluation.
Add-On Code 90785: Interactive Complexity
CPT 90785 is an add-on code that can be billed with 90791 when the evaluation involves specific complexity factors that require additional clinician skill and effort.
Qualifies for 90785
- Patient has communication difficulties (developmental, cognitive, language barrier)
- Third-party involvement affects treatment (parent, guardian, agency)
- Evidence of emotional or behavioral dysregulation during session
- Disclosure of abuse or trauma requiring specialized response
- Need for interpreter services
Does NOT Qualify for 90785
- Patient is simply difficult or resistant
- Complex diagnostic picture alone
- Session ran longer than expected
- Patient has multiple diagnoses
- Routine involvement of family member
Documentation Requirement for 90785
When billing 90785, document the specific complexity factor(s) present and how they affected the evaluation. Simply noting "interactive complexity present" is insufficient. Describe what made the interaction complex and what additional clinical skills were required.
Frequently Asked Questions
Can I bill 90791 and a therapy code (90834/90837) on the same day? ▼
Generally, no. The 90791 evaluation includes the diagnostic interview, mental status examination, and treatment planning components. Billing a separate therapy code for the same encounter would typically be considered duplicate billing. However, if you complete a full evaluation AND provide a distinct psychotherapy service at a separate time on the same day (such as a crisis intervention hours later), both services may be billed with appropriate documentation and modifier -59 on the lesser service.
How long should a 90791 evaluation take? ▼
While 90791 is not a time-based code, most comprehensive psychiatric evaluations require 45-90 minutes of face-to-face time. Evaluations shorter than 45 minutes may be questioned by auditors as potentially incomplete. Very long evaluations (over 2 hours) are appropriate for complex cases but should include documentation explaining why the extended time was clinically necessary. Do not artificially extend or shorten evaluations based on billing considerations.
Can an intern or trainee bill 90791? ▼
This depends on payer rules and state regulations. Medicare has specific "incident to" requirements for services provided by trainees, including direct supervision requirements. Most commercial payers require services to be billed under a licensed, credentialed provider. The supervising clinician typically must be on-site and immediately available. Some payers do not cover trainee services at all. Always verify payer-specific requirements before billing for trainee-provided evaluations.
What is the difference between 90791 and an E/M code for a new patient? ▼
CPT 90791 is a psychiatric-specific evaluation code that includes comprehensive psychiatric history, mental status examination, and diagnostic formulation. E/M codes (99202-99205 for new patients) are general medical evaluation codes based on medical decision-making complexity or time. Psychiatrists and physicians may choose between 90791/90792 and E/M codes based on the nature of the service provided. Non-physician mental health providers typically use 90791 since they cannot bill E/M codes. You cannot bill both an E/M code and 90791 for the same encounter.
Can I bill 90791 for a psychological testing referral evaluation? ▼
It depends on the scope of the evaluation. If you conduct a comprehensive psychiatric diagnostic evaluation and ALSO administer psychological tests, you would bill 90791 for the diagnostic evaluation and the appropriate testing codes (96130-96139) for the testing services. However, if the appointment is primarily for testing with only a brief clinical interview, you would bill only the testing codes. The evaluation must meet the full requirements of 90791 to bill that code.
Is 90791 covered for telehealth? ▼
Yes, most payers cover 90791 via telehealth when provided through real-time audio/video communication. Add the appropriate telehealth modifier (-95 or -GT depending on payer) and use the correct Place of Service code (02 or 10). Some payers may have restrictions on audio-only evaluations. Medicare expanded telehealth coverage for mental health services, though policies continue to evolve. Always verify current telehealth policies with each payer and ensure compliance with state telehealth regulations.
How do I bill if the patient no-shows after the intake is partially complete? ▼
If you began an evaluation but the patient no-showed before completion, you generally cannot bill 90791 since the evaluation was not completed. You may be able to bill a time-based therapy code for the time spent with the patient if that portion included psychotherapy elements, or you may need to document the incomplete evaluation and not bill until the evaluation is completed at a subsequent session. Some practices include no-show fees in their financial agreements for this situation.
Key Takeaways
Master CPT 90791 Billing
CPT 90791 represents the foundation of your billing relationship with each patient. A thorough, well-documented diagnostic evaluation establishes medical necessity for all treatment that follows and sets clear expectations for the therapeutic work ahead. By understanding the requirements, documentation standards, and payer expectations, you can bill this code confidently while providing the comprehensive assessments your patients deserve.
Remember: your intake evaluation requires significant clinical expertise and time investment. Make sure your documentation reflects the comprehensive nature of this service, and ensure your contracted rates appropriately compensate you for the value you provide.
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