This article discusses one of the most important billing codes that therapists will utilize. Most therapists entered the mental health field to support clients in their healing journey- not to learn billing codes. But understanding how to bill ethically and accurately is part of how we sustain our work and ensure clients can access the care they need.
One of the most important billing codes you’ll use is CPT 90791, which represents the first clinical session with a new client- what is called the intake or initial assessment. This session is where you begin to understand who the client is, what they’re navigating, and how therapy can support them.
Here’s what you need to know to use 90791 with clarity and confidence:
What Is CPT Code 90791?
CPT 90791 is used for a comprehensive diagnostic evaluation of the identified client- the first step in forming a clinical understanding of a new client. It includes:
- A clinical interview
- Review of psychiatric, medical, social, and family history
- A mental status exam
- Consideration of cultural and contextual factors that shape the client’s experience
- Preliminary diagnostic impressions
- A treatment plan or clinical recommendations
Even if others are present (like a parent or partner), this code is specifically for evaluating the identified client. All attendees other than the identified patient should be encouraged to complete the agreement for guest participation in services.
When to Use It
- For the first session of a new treatment episode
- When a returning client has been discharged for more than 6 months
- Only if the client is present (in person or virtually).
- If the client is not present (e.g., only a parent or partner attends), 90791 cannot be billed. If only a non-patient attends the first session, no CPT code be billed, as 90791 is required to kick off care and establish the treatment plan.
- Only once per episode of care
CPT code 90791 is the exclusive code for a diagnostic evaluation conducted during the first session, regardless of whether the therapy modality centers 1:1, couples, or family work.
Session Details
- Time requirement: Minimum of 16 minutes; up to 90 minutes is typical. Your notes should reflect the time spent and what was covered.
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Documentation must include:
- Reason for the evaluation
- Psychiatric, medical, and social history
- Cultural and contextual considerations, recognizing how identity and environment impact the client
- Mental status exam
- Clinical impressions and treatment plan
- The client’s participation in the session
- A clinical summary that integrates findings into a cohesive picture of the client’s current functioning and needs
What If You Can’t Complete the Intake?
Not every intake goes as planned, and that’s okay. There are two common scenarios where a full intake might not be possible:
1. The client is present but the evaluation can't be completed
This can happen if:
- The client is in an acute, life-threatening crisis
- The session is cut short (less than 16 minutes)
- The therapist runs out of time (here’s an article about managing time effectively during intakes!)
In this case:
- Document what you completed, why the full evaluation couldn’t be finished, and your plan to continue next session. If the treatment plan was unable to be completed, consider documenting that the current treatment plan is to discuss potential treatment goals and create a treatment plan.
Example note:
“The diagnostic evaluation was started but not completed due to time limitations. Components completed include MSE, psychosocial history, but treatment plan was not addressed. This writer will revisit the treatment plan in further detail with the client in the next session.”
- Only bill 90791 if at least 16 minutes of assessment occurred. You cannot use 90791 again in the next session, even if you continue further assessment. With that said, please be sure that the documentation in the second session records the patient information that was not captured in the initial session.
2. The client is in acute crisis
If a client arrives in emotional or behavioral crisis- experiencing active suicidal ideation with plan, means, and/or intent, panic, or requiring urgent stabilization- your focus may shift from diagnosis to responding to the client’s safety concerns.
In these cases:
- 90791 may not be the appropriate code
- Consider billing CPT 90839 (psychotherapy for crisis, first 60 minutes) instead
Use 90839 when the session is centered on de-escalation, risk assessment, and crisis intervention, not diagnostic work. This article reviews the essential components for being able to bill for crisis intervention using 90839.
You can then complete and bill 90791 in a future session when the client is more stable.
What if the client does not attend?
If the client no-shows or cancels late:
- Do not bill 90791 or any CPT code
- Follow Rula’s no-show policy and attempt to collaborate with the client to determine if the initial needs to be rescheduled or cancelled.
Common Pitfalls to Avoid
- Billing without the client present
- Using a therapy code (like 90837 or 90847) instead of 90791 for the first session
- Submitting incomplete documentation, especially missing the clinical summary, mental status exam, or treatment plan
If billing feels new or overwhelming, that’s okay; it’s just a skill that takes time to develop- and we’re here to support you! For questions about 90791, documentation, or payer policies, start by using the AI search bar on this page. You can get answers instantly or ask to connect with a live Service Team member at any time.
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