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90791 Billing Guide: Psychiatric Diagnostic Evaluation

September 15, 2026 · 3 min read

What Is CPT 90791?

CPT 90791 represents a psychiatric diagnostic evaluation without medical services.

CMS describes 90791 as a psychiatric diagnostic evaluation and distinguishes it from 90792, which includes medical services.

90791 vs 90792

The basic distinction is:

90791: Psychiatric diagnostic evaluation without medical services.

90792: Psychiatric diagnostic evaluation with medical services.

CMS's current Medicare claims manual contains these distinctions.

The correct code depends on the service performed and the provider's scope and qualifications.

What Should the Record Support?

The documentation should support the diagnostic evaluation performed.

Depending on the applicable payer requirements, this may include:

  • Reason for evaluation
  • Relevant history
  • Mental/behavioral assessment
  • Clinical findings
  • Diagnostic formulation
  • Treatment recommendations
  • Medical necessity
  • Provider identity
  • Date of service

The exact documentation requirements vary.

How Often Can 90791 Be Billed?

Providers should not assume that 90791 can be billed repeatedly simply because a patient returns.

CMS contractor guidance states that psychiatric diagnostic procedures may generally be covered once at the outset of an illness or suspected illness, with circumstances in which another evaluation may be appropriate, such as a new episode after a hiatus or admission/readmission. The record needs to support the reason for another diagnostic interview.

Commercial payer policies may differ.

Common 90791 Billing Issues

  • Duplicate or unexpected diagnostic evaluation
  • Incorrect provider type
  • Eligibility problems
  • Credentialing problems
  • Authorization requirements
  • Insufficient documentation
  • Incorrect diagnosis
  • Incorrect place of service

Interactive Complexity and 90791

CPT 90785 is an add-on code for interactive complexity in qualifying circumstances.

CMS identifies 90785 as usable with 90791 and 90792, as well as specified psychotherapy codes.

It should not be added simply because a session was difficult or lengthy. The circumstances must meet the applicable requirements.

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