CPT 90791: Psychiatric Diagnostic Evaluation
CPT 90791: Psychiatric Diagnostic Evaluation, Explained
CPT 90791 is the initial diagnostic evaluation used at the start of a course of behavioral health treatment. It’s not a therapy session, it’s the intake assessment that comes before one.
What is CPT 90791?
90791 covers a psychiatric diagnostic evaluation, a comprehensive intake assessment used to establish a diagnosis, treatment history, and initial treatment plan for a new patient, or a returning patient starting a new episode of care. It doesn’t include medical services (that’s covered separately when applicable), it’s specifically the diagnostic and psychosocial evaluation.
It’s typically a one-time code per episode of care, not something billed at every visit.
When to use it
Use 90791 for the initial comprehensive evaluation when a patient begins treatment, covering history, presenting concerns, risk assessment, and the resulting diagnosis and treatment plan. It’s also appropriate for a re-evaluation when a patient returns after a genuine gap in treatment, not as a routine repeat visit.
Most payers reimburse 90791 once per episode of care. Billing it again for an existing, continuously-treated patient without a clear gap and clinical justification is one of the most common and easily avoidable denial triggers for this code.
What your documentation needs to show
The note needs to reflect a genuine diagnostic evaluation, patient history, presenting problem, relevant psychosocial factors, risk assessment, and the diagnosis and treatment plan that resulted from the evaluation. A note that reads like a regular therapy session rather than an intake assessment weakens the claim.
Common reasons this code gets denied
Billed more than once without justification. The most frequent issue, re-billing 90791 for a patient already in active treatment, without a documented gap in care that supports a new evaluation.
Same-day bundling conflicts. Some payers won’t reimburse 90791 on the same date as a separate therapy session or E/M visit, check your specific payer’s same-day billing rules.
Thin documentation. A note that doesn’t clearly reflect the depth of a diagnostic evaluation, versus a standard session, can get flagged on review.
Related codes
Frequently asked questions
Can we bill 90791 again for an existing patient? +
Only if there’s a genuine gap in treatment and clinical justification for a new evaluation, not as a routine repeat. Most payers limit this to once per episode of care.
Is 90791 the same as a therapy session? +
No. It’s the diagnostic intake evaluation that typically happens before ongoing psychotherapy sessions begin, not a treatment session itself.
Can 90791 be billed the same day as a therapy session? +
It depends on the payer, some bundle the two and won’t reimburse both on the same date. Worth confirming your specific payer’s policy before scheduling an evaluation and a session back to back.
Getting denials on evaluation billing?
We work specifically with behavioral health practices. A free audit looks at your actual claims and shows you exactly what’s behind your denial pattern, not a generic checklist.