CPT 90791 is the standard intake or diagnostic evaluation for non-prescribing mental health clinicians such as psychologists, licensed counselors, social workers, and marriage and family therapists. It establishes the diagnosis and treatment plan without including medical services.
When to use 90791
Bill 90791 for a comprehensive initial assessment that includes a clinical interview, mental status exam, and diagnosis. Use it once per provider per episode of care; for a re-evaluation after a significant gap, a 90791 may be billed again if supported by medical necessity. Prescribers who also perform medical assessment use 90792 instead.
How to bill it
Report a single unit for the evaluation, typically 30–90 minutes. Do not bill 90791 with an E/M service, and do not add psychotherapy on the same date unless a separate, clearly documented service is delivered.
Common pitfalls
- Billing 90791 and an ongoing psychotherapy code on the same day without distinct documentation.
- Using 90791 for routine follow-up appointments rather than a true diagnostic evaluation.
Frequently asked questions
Can a non-prescribing therapist bill 90791?
Yes. 90791 is designed for clinicians who do not provide medical services. Prescribing providers who include a medical history and medical decision-making must use 90792 instead.
How often can 90791 be billed?
Generally once per provider per episode of care. A repeat evaluation may be justified after an extended break, a significant change in clinical status, or transfer from another provider, supported by documentation.