CPT Code 90791: Psychiatric Diagnostic Evaluation Guide

CPT 90791 covers a comprehensive psychiatric diagnostic evaluation – the foundational assessment that informs the entire treatment plan. This is typically the first billable service when a new patient enters treatment.

The evaluation encompasses a thorough psychiatric history, mental status examination, review of relevant medical history, psychosocial assessment, diagnostic formulation, and initial treatment recommendations. It's the clinical foundation upon which all subsequent treatment decisions are built.

This code is used by psychiatrists, psychologists, licensed clinical social workers, licensed professional counselors, and other qualified mental health professionals.

N/A – billing code. The evaluation itself must include:

• Chief complaint and history of present illness
• Psychiatric history (prior diagnoses, treatments, hospitalizations)
• Medical history and current medications
• Family psychiatric history
• Social/developmental history
• Substance use history
• Mental status examination
• Risk assessment (suicidality, homicidality, self-harm)
• DSM-5 diagnostic formulation
• Treatment recommendations

Comprehensive documentation must include:

• Referral source and reason for evaluation
• Detailed history of present illness with timeline
• Past psychiatric treatment history with outcomes
• Current and past medications with responses
• Complete mental status examination
• Standardized assessment results if administered
• Diagnostic impressions with DSM-5 codes
• Differential diagnoses considered and ruled out
• Clinical formulation integrating biopsychosocial factors
• Treatment plan with specific recommendations
• Risk assessment and safety planning if indicated

N/A – billing code. Distinguish from:

• 90792 – psychiatric evaluation WITH medical services (prescribing)
• 90837 – ongoing therapy (not initial evaluation)
• 96130-96131 – psychological testing/evaluation
• 99202-99205 – E/M new patient visit (medical, not psychiatric)
• Re-evaluations that don't warrant a new 90791 (use therapy codes instead)

The 90791 evaluation should culminate in:

• Clear diagnostic formulation with primary and secondary diagnoses
• Prioritized problem list
• Evidence-based treatment recommendations
• Recommended level of care
• Frequency and modality of treatment
• Measurable treatment goals
• Criteria for treatment success and discharge
• Referrals for additional services as needed
• Safety plan if risk factors identified

Key billing information:

• Most payers allow 1-2 evaluations per patient per year
• Typical reimbursement: $120-200 depending on payer
• Some payers require 90791 before covering ongoing therapy
• Can be billed on the same day as 96127 (brief assessment)
• Generally should NOT be billed with therapy codes on the same date
• Can add 90785 for interactive complexity
• Prior authorization is rarely required for initial evaluation
• Telehealth evaluations are generally covered

Monitor:

• Payer policies on how often 90791 can be repeated
• Documentation requirements for managed care organizations
• Telehealth evaluation policies and requirements
• Changes in required evaluation components
• Collaborative care model billing (if applicable)

Avoid:

• Using 90791 for routine therapy sessions (even if assessment-heavy)
• Repeating 90791 too frequently without clinical justification
• Incomplete evaluations missing key components (MSE, risk assessment)
• Not formulating a clear diagnostic impression
• Failing to develop specific, measurable treatment recommendations
• Billing 90791 and 90837 on the same date without justification
• Copy-forwarding evaluation templates without individualizing