The world of behavioral health billing can seem daunting, especially with the complexities of CPT codes and insurance requirements. One of the most essential — yet frequently misunderstood — codes in mental health billing is CPT code 90791. This guide will explain what 90791 is, when and how to use it, key billing and documentation tips, and how to maximize reimbursement while staying compliant.
What Is CPT Code 90791?
CPT code 90791 is defined as the “Psychiatric diagnostic evaluation.” This code is used for an initial assessment of a patient by a mental health provider, such as a psychologist, psychiatrist, clinical social worker, or counselor. Unlike many other CPT codes, 90791 does not include medical services or procedures — it focuses on the evaluation and diagnosis of mental health conditions.
Key features of 90791:
- Used for the first visit with a new client or returning client after a significant lapse in care.
- Involves a comprehensive evaluation: gathering history, assessing mental status, diagnosing, and developing an initial treatment plan.
- No medical services or physical exam are required — if those are included, a different code (like 90792) may apply.
When Should 90791 Be Used?
The 90791 code is billed for initial diagnostic assessments. It is appropriate when:
- The client is new to your practice.
- There has been a long gap since the last evaluation (varies by payer, but often 1+ years).
- There is a need for a re-evaluation due to a significant change in clinical status or diagnosis.
- The provider is performing a formal intake and assessment to determine diagnosis and treatment recommendations.
Note: 90791 is not meant for ongoing therapy sessions or brief check-ins. It’s exclusively for comprehensive diagnostic assessments.
Who Can Bill 90791?
Providers who can typically bill 90791 include:
- Psychiatrists
- Psychologists
- Licensed Clinical Social Workers (LCSW)
- Licensed Professional Counselors (LPC)
- Marriage and Family Therapists (MFT)
- Nurse Practitioners (with behavioral health training)
Billing eligibility may vary based on state and insurance guidelines, so always verify provider type with each payer.
90791 vs. 90792: What’s the Difference?
A source of confusion is the difference between 90791 and 90792. The distinction is important for correct billing:
- 90791: Psychiatric diagnostic evaluation without medical services — for non-prescribing providers (psychologists, social workers, counselors, etc.)
- 90792: Psychiatric diagnostic evaluation with medical services — for medical providers (psychiatrists, psychiatric NPs, or PAs) who may conduct a physical exam or prescribe medication.
Billing Guidelines for 90791
Getting paid for 90791 starts with understanding payer rules and best practices. Here’s what you need to know:
1. Frequency Limits
Most insurers allow 90791 only once per patient per provider within a certain time frame (usually once per year). Some plans may approve a second 90791 for a re-evaluation if medically necessary, but prior authorization and documentation are required.
2. Session Duration
Typically, a 90791 session lasts 60 minutes (range: 45-90 minutes). Do not bill 90791 for shorter, routine sessions — use therapy codes (e.g., 90834 or 90837).
3. Place of Service
90791 can be billed for in-person or telehealth evaluations (check if the payer accepts telehealth). Document the place of service accurately.
4. Modifiers
Use modifiers when required by insurance (e.g., 95 for telehealth, GT for synchronous telemedicine). Some payers may require additional modifiers for specific circumstances (e.g., H codes for Medicaid).
5. Multiple Providers
If a client sees more than one provider for an initial evaluation (e.g., a psychologist and a psychiatrist), each provider may bill 90791 or 90792 — but only if services are on different days or for distinct diagnostic purposes. Coordination and clear documentation are vital to avoid claim denials.
90791 Documentation Requirements
Accurate, detailed documentation is essential for compliance and reimbursement. Here’s what most payers expect in a 90791 note:
Required Elements:
- Reason for referral/intake
- Comprehensive history (psychiatric, medical, family, social, and developmental)
- Current symptoms and presenting concerns
- Mental status examination (appearance, behavior, mood, cognition, thought process, insight, judgment)
- Diagnosis (using DSM-5 or ICD-10 criteria)
- Assessment of risk (suicidality, homicidality, substance use, safety concerns)
- Initial treatment plan (goals, recommendations, referrals, follow-up)
- Time spent and mode of delivery (in-person, telehealth)
Tip: Always tailor documentation to payer requirements and clinical best practices. Thorough, organized intake notes protect against audits and justify medical necessity.
Sample 90791 Intake Note Template
Here’s a basic structure you can use (customize as needed):
- Patient Name/ID
- Date of Service
- Reason for Visit
- Presenting Problem/Symptoms
- History (Psychiatric, Medical, Family, Social, Developmental)
- Mental Status Exam
- Assessment and Diagnosis
- Risk Assessment
- Treatment Plan
- Time Spent
Reimbursement for 90791
Reimbursement rates for 90791 vary based on insurance type, provider credentials, and location.
How Much Does 90791 Pay?
- Medicare (2024): Around 160−160 – 200 per session
- Commercial insurance: Reimbursement can range from 120to120 to 250
- Medicaid: Typically pays less than Medicare or commercial plans
Tip: Always verify rates with each payer and update your fee schedule annually.
How to Maximize Reimbursement
- Confirm client eligibility and benefits before the session.
- Submit claims promptly and follow up on denials.
- Use correct codes and modifiers; double-check for errors.
- Maintain detailed documentation that demonstrates medical necessity.
- Consider prior authorization for complex cases or re-evaluations.
Common Billing Mistakes with 90791
Avoid these pitfalls to ensure faster payment and fewer denials:
- Using 90791 for routine therapy: Use 90832/90834/90837 for psychotherapy, not 90791.
- Inadequate documentation: Missing required elements or rationale for the evaluation.
- Overuse: Billing multiple 90791s per client without clear justification.
- Wrong provider type: Only bill 90791 if you meet payer criteria for that code.
- Forgotten modifiers: Omitting telehealth or other mandatory modifiers.
Frequently Asked Questions (FAQ)
Can I bill 90791 and a therapy code (like 90834) on the same day?
Generally, no. Most payers only allow one primary service per day, unless there are distinct, medically necessary services and each is clearly documented.
How often can I bill 90791 for the same patient?
Usually once per year per provider. Additional 90791s may require prior authorization and solid documentation.
Can I bill 90791 for telehealth sessions?
Yes, if the payer allows — always attach the proper telehealth modifier (e.g., 95 or GT) and document the session as telehealth.
Who cannot bill 90791?
Medical providers who perform a physical exam or prescribe medication should use 90792 instead. Also, check if state law or specific payer rules restrict billing by certain provider types.
Tips for Efficient 90791 Billing and Documentation
- Automate intake forms to gather comprehensive patient history before the appointment.
- Use EHR templates that prompt for all required 90791 documentation elements.
- Train staff on payer-specific requirements and common billing pitfalls.
- Track denials and appeals to identify trends and correct systemic issues.
Conclusion
CPT code 90791 is a cornerstone of mental health billing, enabling providers to perform comprehensive psychiatric diagnostic evaluations and develop effective treatment plans. By understanding when and how to use 90791, maintaining thorough documentation, and following payer guidelines, you can streamline your billing process, reduce denials, and maximize your reimbursement.
Stay up to date with payer requirements and invest in ongoing staff education to ensure long-term success in behavioral health billing. If in doubt, consult payer policy manuals or reach out to professional billing consultants.