CPT 90791 is the code for a psychiatric diagnostic evaluation (without medical services). Use it for a comprehensive intake assessment – for example, a new-patient evaluation or any encounter focused on establishing a mental health diagnosis. Documentation must cover the chief complaint, history of present illness, psychosocial and family history, review of relevant systems, and a complete mental status examination. 1 This code is used when evaluation (not therapy) is the primary purpose of the visit.
90791 can be billed by qualified behavioral health professionals. This typically includes:
Psychiatrists (MD/DO) and psychiatric nurse practitioners or physician assistants performing evaluations. 2
Psychologists (PhD/PsyD) conducting diagnostic interviews. 2
Clinical social workers, counselors, and marriage/family therapists, where state law and payer policy permit.
Other licensed mental health clinicians (e.g. clinical nurse specialists) working within their scope.
The service is most often provided in outpatient or office-based settings (private practice, community clinics, therapy offices). For hospital or inpatient admissions, Medicare usually uses a standard E/M code or 90792 (if medical assessment is included) for the first day of care. 2 In contrast, 90791 is generally an outpatient code (including telehealth) for psychiatric intake services.
90791 is not a timed code, but it represents a detailed evaluation. In practice, an intake evaluation often lasts 50–90 minutes. 3 Clinicians should document all necessary elements to support the complexity of the evaluation: full psychiatric history, findings on mental status exam, risk assessment (suicide/homicide/self-care), diagnosis, and a treatment plan. If an evaluation clearly extends beyond 90 minutes, check payer rules: some carriers allow add-on codes or expect the use of timed psychotherapy codes (90837/38) for the extra time. Always record the total face-to-face time if billing over 90 minutes.
Medicare: 90791 is covered as an outpatient psychiatric service. It is paid at 80% of the Medicare Physician Fee Schedule. Importantly, it is not subject to the old outpatient mental health visit cap; it’s reimbursed like any other medical service. 1 Medicare rules allow one 90791 at the onset of a treatment episode, and permit repeating it only after a significant break (roughly 6 months of no care) or a major change in the patient’s condition. 2 For example, after a psychiatric hospitalization or a long gap, the same provider can bill a new 90791.
Medicaid: State Medicaid plans usually follow Medicare’s lead. They typically cover 90791 for initial assessments and may impose similar limits on frequency. Clinicians should check specific state Medicaid or managed care rules for any differences.
Commercial Insurers: Private payers also cover 90791 for intake evaluations. Most plans limit it to one billing per patient per benefit period (often once per year) and require medical necessity for repeats. Routine authorizations for a standard intake are rarely required, but policies vary by carrier. Note that 90791 should not be billed on the same day as psychotherapy (90832–90838) or general medical E/M codes; those services require separate codes.
CPT 90791 is included on Medicare’s permanent telehealth services list, so it can be provided via live interactive video. 3 When billing telehealth for 90791, use the appropriate modifier and place of service:
Modifier: Use modifier 95 for synchronous telehealth (CMS requires this modifier; 4 many commercial plans also recognize 95 or GT).
Place of Service: For Medicare, use POS 02 (Telehealth). Some providers bill POS 11 (office) with modifier 95 for telehealth; check each payer’s rules.
Parity: Mental health parity laws generally require that telehealth visits be covered comparably to in-person care. However, verify coverage specifics (for example, copays or facility fees may differ). Note that CPT 90791 requires a full diagnostic assessment; most payers do not allow audio-only (telephone) encounters for this code unless explicitly permitted.
Telehealth delivery of 90791 can improve access (especially in rural or underserved areas) while ensuring clinicians are reimbursed for the full diagnostic interview.
New Patient Intake: The most routine use of 90791 is a first-visit evaluation. The clinician gathers a detailed psychiatric history and assesses symptoms to arrive at diagnoses and a treatment plan.
Transitions of Care: When a patient enters a new care setting or provider (for example, after hospital discharge or changing therapists), 90791 establishes the current status. CMS specifically permits a new psychiatric evaluation after inpatient care or a significant clinical change. 4
Periodic or Annual Reassessment: In some practices, especially for chronic or complex cases, a thorough annual checkup may be billed as 90791 (subject to payer rules). This is essentially a comprehensive re-evaluation of the patient’s condition.
Extended/Complex Evaluations: If an intake truly requires multiple sessions (e.g. separate family interviews), insurers may allow billing 90791 on more than one day. Guidelines note that additional evaluation—such as interviewing a child and then the parent separately—can justify a second diagnostic interview code. 1
(Recall that 90791 is an evaluation code only. If psychotherapy is also delivered in the same encounter, use the appropriate combination of evaluation and therapy codes, not 90791.)
Using CPT 90791 properly ensures that the comprehensive evaluation effort is recognized. This code typically carries higher reimbursement than a standard therapy visit (reflecting its length and complexity), helping small practices cover the cost of in-depth intakes. For patients, a CPT 90791 visit means a complete, documented assessment on day one, which guides better-personalized care. In short, 90791 supports quality treatment planning while ensuring clinicians are compensated for this critical service.
Sources:
American Psychiatric Association - CPT Primer for Psychiatrists (Nov 2013) https://www.psychiatry.org/File%20Library/Psychiatrists/Practice/Practice-Management/Coding-Reimbursement-Medicare-Medicaid/Coding-Reimbursement/cpt-primer-for-psychiatrists.pdf
CMS - Billing and Coding: Psychiatry and Psychology Services (A57480) (Nov 2024) https://www.cms.gov/medicare-coverage-database/view/article.aspx?articleId=57480
Telehealth.HHS.gov - Billing for telebehavioral health (Jan 2025) https://telehealth.hhs.gov/providers/best-practice-guides/telehealth-for-behavioral-health/billing-for-telebehavioral-health
American Medical Association - Special coding advice during COVID-19 public health emergency (Sep 2021) https://www.ama-assn.org/system/files/covid-19-coding-advice.pdf
