Coding · July 11, 2026 · 6 min read

CPT 90791 & 90792: Billing the Psychiatric Diagnostic Evaluation

Every treatment episode starts with a diagnostic evaluation — and a coding decision. 90791 and 90792 are the intake codes of behavioral health, split by one question: were medical services part of the eval? Getting them right matters because intake denials poison the whole episode that follows.

The difference in one line

90791 is a psychiatric diagnostic evaluation without medical services — the standard intake for therapists, psychologists, and clinical social workers. 90792 is the same evaluation with medical services (medical history, mental status exam with medical lens, medication assessment or prescribing) — billed by psychiatrists, psychiatric NPs, and PAs.

Frequency rules: the denial trap

Most payers cover one diagnostic evaluation per provider (or practice) per episode of care, and many limit how often it can repeat — commonly once every 6 or 12 months unless there's a significant clinical change or a new treatment episode. The classic denial: a patient transfers between clinicians in the same group and both bill 90791 within weeks. Check payer policy before re-billing an eval, and document the clinical justification when one is genuinely warranted.

Documentation requirements

• Complete biopsychosocial assessment — presenting problem, history, mental status exam, risk assessment.
• Diagnosis with supporting clinical findings.
• Initial treatment plan — level of care, modality, frequency.
• For 90792: the medical elements — medical history review, medication evaluation or initiation — that justify the medical-services code.

Billing notes worth knowing

• Prescribers can often use an E/M new-patient visit (99202–99205) instead of 90792 — the better choice depends on the visit's content and payer rates. See psychiatry E/M coding.
• 90791/90792 generally can't be billed the same day as a psychotherapy code by the same provider; crisis codes (90839/90840) have their own same-day exclusions.
• Interactive complexity (90785) can be added when communication barriers complicate the eval — commonly with children.
• Both codes are telehealth-eligible with correct modifiers and POS.

The intake eval also sets up everything billing-wise: eligibility, benefits, and authorization for the episode ahead. That front-end work is where AI billing and a clean intake process pay for themselves. Full code list: behavioral health CPT reference.

This guide is for general reference only. CPT codes, HCPCS codes, and payer rules change, always verify against current coding guidance and your specific payer policies. CPT is a registered trademark of the American Medical Association.