Understanding the 90791 CPT Code: A Complete Guide for Behavioral Health Billing

The CPT Code 90791 is a cornerstone for billing psychiatric diagnostic evaluations. Whether you’re a psychiatrist, licensed clinical social worker, psychologist, or a medical billing expert, it’s essential to grasp the nuances of this code to ensure accurate reimbursement, reduce denials, and stay compliant with insurance requirements.  

What Is the 90791 CPT Code?

CPT Code 90791 is defined as, psychiatric diagnostic evaluation without medical services. It is used during the initial assessment of a patient’s mental health status and is typically billed once at the start of treatment. This service includes gathering a patient’s history, evaluating their mental status, and creating a treatment plan, but does not include any physical examination or medical services like prescribing medication.

When and How to Use the 90791 CPT Code?

The CPT code 90791 can be use for:

• For initial assessments performed by non-medical providers (e.g., psychologists, LCSWs, LMFTs).
• When no physical exam or prescription is involved.
• To assess mental status, psychosocial history, and diagnostic impressions.
• Often limited to once per provider, per patient, per episode of care, unless there’s medical justification for additional evaluations.

How Is 90791 Different from 90792?

90791 is appropriate when no medications are prescribed and no physical exams are conducted. If the session includes such elements, 90792 should be used instead.

How Much Does CPT 90791 Pay?

Reimbursement rates vary by payer, state, and provider type. However, Medicare’s 2024 national average reimbursement is approximately:

• $160 to $190 per session (45-60 minutes)

Private insurers may pay more or less depending on your contract. Always verify rates through payer fee schedules.

How Do You Bill the 90791 CPT Code Correctly?

To ensure successful claims submission:

1. Use the correct diagnosis code (ICD-10) to support medical necessity.
2. Add place of service (POS) code, like:

• 11 for Office
• 02 for Telehealth (Medicare may require modifier too)

3  Include NPI and Taxonomy Code for eligible provider types.

4  Ensure documentation includes:

• Reason for assessment
• History and mental status exam
• Initial diagnosis
• Recommended treatment plan

How Often Can You Bill 90791?

• Typically allowed once per provider, per patient at the start of treatment.
• May be billed more than once if the patient returns after a long gap or is re-evaluated due to a significant change in mental status.
• Always check payer-specific guidelines for frequency limits.

How Do Modifiers Work with 90791?

• Modifiers help clarify the context of the service. Examples:
• 95 or GT – For telehealth services
• 59 – If billing 90791 with other procedures on the same day (rare)
• H1, H2 – Medicaid state-specific modifiers (check local guidelines)

How to Document a 90791 Session?

Proper documentation is critical for reimbursement and audits. Include:

• Chief complaint
• Psychiatric history
• Mental status exam
• Risk assessment (e.g., suicidal ideation)
• DSM-5 diagnosis
• Treatment plan and follow-up recommendation

How Is 90791 Used in Telehealth?

Telehealth exploded post-COVID, and 90791 remains eligible for virtual delivery.

• CMS and most payers accept 90791 via telehealth
• Use POS 02 or 10 and modifier 95
• Confirm patient consent and HIPAA-compliant platform
• Ensure state licensure compliance (especially for out-of-state sessions)

How Do State & Federal Laws Impact 90791 Billing?

Here are a few key compliance considerations:

• HIPAA: Protect all documentation and recordings
• Parity Laws: Require equal reimbursement for mental health services
• State Licensure: Check your state board’s approval for billing 90791
• Medicare/Medicaid: They may have specific frequency or provider type restrictions

Common Billing Errors with 90791 — And How to Avoid Them

• Wrong provider type billing 90791 (e.g., medical doctors)
• Using 90791 and 90792 together on the same day without justification
• Missing modifiers for telehealth
• Insufficient documentation (e.g., no diagnosis or treatment plan)
• Exceeding allowed frequency without payer approval

How to Optimize Reimbursement for 90791?

• Verify payer-specific policies in advance
• Include strong clinical documentation and DSM-5 diagnosis
• Check if patient has met deductible
• Track denials by payer and appeal with proper justification
• Use credentialed providers only — insurance won’t pay otherwise

Final Thoughts: Why 90791 Matters for Behavioral Health Practices

The 90791 CPT code plays a vital role in launching accurate and effective mental health treatment plans. It sets the clinical and billing foundation for understanding a patient’s psychiatric needs through a comprehensive diagnostic evaluation. When billed and documented correctly, it ensures appropriate reimbursement and supports compliance with payer regulations. For behavioral health practices, mastering 90791 is essential to delivering quality care and maintaining financial stability.