Psych diagnostic evaluation
CPT code 90791 is used when a mental health professional conducts an initial psychiatric evaluation to diagnose a patient's mental health condition. This is the first comprehensive assessment without medical services like prescribing medication.
RVU breakdown
Conversion factor: 32.3465 · Source: CMS MPFS RVU25A · Confidence: High
Billing tips
Bill 90791 only once per patient per provider (or group practice) for initial diagnostic evaluation; subsequent evaluations should use 90792 if medical services included or psychotherapy codes with evaluation component
Impact: Prevents denials for duplicate diagnostic evaluations; billing 90791 multiple times for same patient typically results in denial unless clearly separated episodes of care with different diagnoses
Verify that no medical services (medication prescription, interpretation of lab results, physical examination) are provided during the encounter; if medical services are included, bill 90792 instead
Impact: 90792 reimburses at $183.78 non-facility versus $166.91 for 90791, a difference of $16.87 when medical services are documented
Ensure evaluation is 60+ minutes to support medical necessity; document total face-to-face time and all diagnostic activities including mental status examination, history gathering, and treatment planning
Impact: Insufficient time documentation is a leading audit trigger; typical evaluation duration is 60-90 minutes to support complexity and reimbursement
For telehealth claims, append modifier 95 and verify originating and distant site requirements are met, including patient consent documentation
Impact: Missing telehealth modifiers result in automatic denials; proper modifier use maintains full reimbursement at $166.91 for non-facility rate
Do not bill 90791 on the same date as psychotherapy codes (90832-90834, 90836-90838) for the same patient; the diagnostic evaluation includes treatment planning but not psychotherapy intervention
Impact: Bundling edits will deny psychotherapy billed same date; separate visits required or delay psychotherapy to subsequent appointment
For Medicare patients, verify non-physician practitioners (LCSWs, LPCs) meet Medicare credentialing requirements and bill at 75% of physician fee schedule when applicable based on state scope of practice
Impact: Non-credentialed providers result in 100% claim denial; proper credentialing ensures payment at appropriate rate (potentially $125.18 for non-physician practitioners versus $166.91 for physicians)
Common denials
Duplicate diagnostic evaluation - 90791 billed more than once for same patient by same provider/group without documentation of new episode of care
How to appeal: Submit medical records demonstrating distinct episode of care with significant time gap (typically 6+ months) and different presenting problem or diagnosis; include discharge summary from previous treatment and new referral documentation
Medical necessity not established - insufficient documentation of psychiatric symptoms, diagnoses, or complexity warranting comprehensive diagnostic evaluation
How to appeal: Provide complete diagnostic evaluation report including detailed mental status exam, psychiatric history, symptom severity assessment, differential diagnosis, and treatment plan; include referring provider documentation supporting need for evaluation
Bundled with same-day psychotherapy or E/M service - payer considers diagnostic component included in other service billed same date
How to appeal: Submit documentation proving services were distinct and separate with modifier 59 if appropriate; alternatively, consider rebilling with correct code (90792 if medical services included, or psychotherapy code if therapy provided); may need to adjust claim to different date of service if services were not truly separate
Provider credentials or enrollment issues - provider not enrolled as mental health specialist or lacks appropriate licensure for independent billing
How to appeal: Submit proof of current license, state scope of practice regulations, and Medicare/payer enrollment documentation; for supervised services, include incident-to documentation and supervising provider credentials; may need to resubmit under supervising provider NPI
Frequently asked questions
What is the difference between CPT code 90791 and 90792?
CPT 90791 is a psychiatric diagnostic evaluation without medical services, while 90792 includes medical services such as prescribing medication, ordering or interpreting lab tests, or performing physical examination components. Use 90791 when only diagnostic assessment and psychotherapy treatment planning occur, and 90792 when the psychiatrist or qualified provider also provides medical interventions. The 2025 Medicare reimbursement differs: $166.91 for 90791 versus $183.78 for 90792 in non-facility settings.
How often can you bill CPT code 90791 for the same patient?
CPT 90791 should typically be billed only once per patient per provider or group practice for an initial diagnostic evaluation. Subsequent diagnostic evaluations may be billed with appropriate documentation showing a distinct new episode of care, significant time gap (usually 6+ months to a year), different diagnosis, or change in clinical status warranting comprehensive re-evaluation. Most payers scrutinize multiple 90791 claims for the same patient and may deny as duplicates without clear medical necessity documentation.
Can psychologists bill CPT code 90791?
Yes, licensed clinical psychologists can bill CPT 90791 for psychiatric diagnostic evaluations within their scope of practice. Psychologists should append modifier AJ when required by Medicare contractors. The reimbursement rate is the same as for psychiatrists ($166.91 Medicare non-facility rate in 2025), though psychologists cannot bill 90792 as it requires medical services beyond their scope of practice in most states.
What is the typical time requirement for CPT code 90791?
While CPT 90791 is not explicitly time-based, a comprehensive psychiatric diagnostic evaluation typically requires 60-90 minutes of face-to-face time with the patient to support medical necessity and documentation requirements. The time should be documented in the medical record along with all components of the evaluation including history, mental status exam, diagnosis, and treatment planning. Evaluations significantly shorter than 60 minutes may face increased audit scrutiny.
Can you bill 90791 and psychotherapy on the same day?
No, CPT 90791 should not be billed on the same day as psychotherapy codes (90832, 90834, 90837, 90846, 90847, 90853) for the same patient. The diagnostic evaluation includes treatment planning but not therapeutic intervention. Payers have bundling edits that will deny one of the services when billed together. Best practice is to complete the diagnostic evaluation (90791) on the first visit and begin psychotherapy on subsequent appointments.
Does CPT 90791 require a diagnosis code?
Yes, CPT 90791 requires at least one ICD-10 diagnosis code to establish medical necessity. If a definitive psychiatric diagnosis cannot be established during the initial evaluation, you may use 'unspecified' diagnosis codes or R-codes (symptom codes) such as R45.851 (suicidal ideations), R45.1 (restlessness and agitation), or Z codes for encounter circumstances. However, the diagnostic evaluation report should document the assessment process and differential diagnosis considerations even when using unspecified codes.
What is the Medicare reimbursement for CPT 90791 in 2025?
The 2025 Medicare national average reimbursement for CPT 90791 is $166.91 for non-facility (office) settings and $142.97 for facility settings. The code has 5.16 total RVUs (3.84 work RVU, 1.22 non-facility PE RVU, 0.48 facility PE RVU, and 0.1 MP RVU) multiplied by the 2025 conversion factor of 32.3465. Actual reimbursement varies by geographic location based on local GPCI adjustments and individual payer contracts.