CPT Code 90791: The Complete Guide to Psychiatric Diagnostic Evaluation

CPT code 90791 is one of the most commonly used billing codes in behavioral health. Whether you're a mental health provider, practice administrator, or billing specialist, understanding how and when to use 90791 is essential for clean claims and maximum reimbursement.

In this article, we’ll break down:

• What CPT code 90791 is
• When to use 90791
• Documentation requirements
• Reimbursement rates
• Common billing errors and how to avoid them

What is CPT Code 90791?

CPT 90791 refers to a psychiatric diagnostic evaluation with no medical services. It is typically used for an initial intake or comprehensive evaluation by a licensed mental health professional such as a psychologist, licensed clinical social worker (LCSW), or counselor.

This service includes:

• A biopsychosocial assessment
• Patient history
• Mental status exam
• Diagnostic impressions
• Treatment planning

Important: 90791 does not include medical services such as prescribing medications or a physical exam. For those, you would typically use 90792 (psychiatric diagnostic evaluation with medical services).

When to Use 90791

Use CPT code 90791 for the first appointment when a provider conducts a full clinical intake. Most payors allow this code to be billed once per provider per patient, though some allow it annually for re-evaluation.

Who Can Bill 90791?

Generally accepted provider types include:

• Psychologists (PhD or PsyD)
• Licensed Clinical Social Workers (LCSW)
• Licensed Professional Counselors (LPC)
• Marriage and Family Therapists (LMFT)

Psychiatrists can also use 90791, but if they are performing a medical evaluation, 90792 may be more appropriate.

Documentation Requirements for 90791

To support CPT 90791, documentation should include:

• Chief complaint and presenting problem
• History of present illness
• Past psychiatric, medical, and family history
• Social and developmental history
• Mental status examination
• Diagnostic formulation
• Initial treatment plan

Incomplete documentation can lead to claim denials or recoupments. Make sure all required elements are clearly outlined in the note.

Reimbursement Rates for 90791

Medicare and commercial insurance reimbursement varies by geography, provider type, and setting. On average:

• Medicare reimburses ~$145–$160 for 90791
• Commercial payors may reimburse between $120–$250

It's always best to verify payor-specific rates through your fee schedules or clearinghouse.

Common Billing Pitfalls (And How to Avoid Them)

Final Takeaway

CPT 90791 is foundational to behavioral health billing, but using it incorrectly can delay payments or trigger audits. Ensure proper documentation, know your payor rules, and train your clinical team to understand the billing implications of intake appointments.

Want to streamline intake compliance or prevent audit risk? Tools like Brellium automatically check 90791 notes for completeness and alignment with payor guidelines.