CPT 90791 — Psychiatric Diagnostic Evaluation

What CPT 90791 is

CPT 90791 is the AMA billing code for a psychiatric diagnostic evaluation without medical services. The full descriptor reads "Psychiatric diagnostic evaluation" — the "without medical services" distinction separates it from CPT 90792, which includes medication evaluation and management.

Unlike psychotherapy codes, 90791 has no minimum time requirement in the AMA descriptor. In practice, these evaluations run 45–90 minutes — long enough to cover presenting complaints, mental health history, family history, prior diagnoses, current functioning, and a preliminary treatment plan.

Medicare rates above are national unadjusted averages from the 2026 Physician Fee Schedule final rule (CMS-1832-F, effective January 1, 2026). Actual payment varies by locality through Geographic Practice Cost Index (GPCI) adjustments.

Who bills 90791

Any licensed mental health professional authorized to conduct diagnostic evaluations under their state's scope-of-practice law. In most states, that includes:

• Licensed Psychologists (PhD, PsyD)
• Licensed Clinical Social Workers (LCSWs)
• Licensed Marriage and Family Therapists (LMFTs)
• Licensed Professional Counselors (LPCs) / Licensed Mental Health Counselors (LMHCs)
• Psychiatrists (MD, DO) — though psychiatrists who conduct medication evaluation alongside the diagnostic intake typically bill 90792 instead

Credential requirements for independent billing vary by state. Some payers credential and reimburse these provider types at different contracted rates for the same code.

90791 vs 90792 — the medical services distinction

The entire difference between these two codes is whether medical services were provided during the evaluation.

• 90791 — Psychiatric diagnostic evaluation. No medication evaluation or management. Billed by therapists, counselors, social workers, and psychologists.
• 90792 — Psychiatric diagnostic evaluation with medical services. Includes medication assessment, prescribing, or management as part of the intake. Typically billed by psychiatrists (MD, DO) and psychiatric nurse practitioners (PMHNPs).

The practical rule: if you cannot prescribe, you bill 90791. If the evaluation included a prescribing decision — whether to start, adjust, or defer medication — 90792 is the appropriate code. Billing 90792 when no medical services were rendered is a documentation and compliance risk.

Some payers will reject 90792 claims from non-prescribing providers entirely. Check payer policy before submitting.

Frequency and billing patterns

90791 is typically billed once per episode of care — at the start of a new treatment relationship. Most payers define "episode" as a continuous period of care with the same provider, though policies vary. Billing it again after a gap in treatment (often 6–12 months, depending on the payer) is generally allowed.

Annual comprehensive reassessments may also support a second 90791 in some circumstances, but prior authorization is frequently required. Payer-specific rules to know:

• Pre-authorization: Many commercial payers require prior authorization for 90791. Obtain authorization before the intake whenever the payer requires it — retroactive authorization is rarely granted.
• Frequency limits: Most commercial payers limit 90791 to once per year per provider, sometimes once per lifetime of the plan benefit. Verify in the payer's clinical policy bulletin.
• Bundling: 90791 is generally not billed on the same day as psychotherapy codes (90832, 90834, 90837). If the initial evaluation extends into a treatment session, use only 90791.

Commercial rate context for 90791

RateScope does not currently publish commercial rate benchmarks for CPT 90791. The pipeline covers psychotherapy codes (90832, 90834, 90837) in the initial Texas rollout, with diagnostic evaluation codes in a later phase.

The Medicare non-facility rate (~$163) is a reasonable reference floor for commercial negotiations. Commercial payers typically contract at a multiplier above Medicare — though that multiplier varies significantly by payer, market, and credential type. For context, Texas commercial payers contract CPT 90837 (a high-frequency psychotherapy code) at medians of $96–$110 for master's-level therapists, while Medicare pays ~$167 for that same code.

If commercial benchmarks for 90791 would inform a contract decision you're facing now, the notify list gets early access when new codes are published.

Common modifiers

Modifier requirements vary by payer. Check the specific payer's billing guidelines before submitting.

See also

• CPT 90837 — Psychotherapy, 53+ minutes
• CPT 90834 — Psychotherapy, 38–52 minutes
• RateScope methodology