CPT Code 90791: The Definitive Guide [+Reimbursement Rates]

Learn everything about CPT Code 90791, billing for psychiatric diagnostic evaluation, also known as a mental health intake session in common parlance.  We teach you about authorization requirements, pay rate increases, frequency of billing, CPT Code 90791 documentation requirements and coding requirements, and more.

Procedure code 90791, along with 90834 and 90837, is one of the most frequently billed CPT codes for licensed behavioral health providers.

CPT Code 90791 Description

CPT Code 90791 is defined as:

An integrated biopsychosocial assessment, including history, mental status, and recommendations. 

This procedure code is used for diagnostic evaluation of new behavioral health concerns and or illnesses, or upon treatment of a new client.

CPT Code 90791 is typically billed for the initial intake appointment a client will have.  Subsequent sessions will be billed with procedure codes 90834 and 90837, depending on the appointment duration.

It can be billed by Licensed Clinical Social Workers (LCSW), Licensed Professional Counselors (LPC), Licensed Mental Counselors (LMHC), Licensed Marriage Family Therapists (LMFT), clinical psychologists, and psychiatrists.

90791 CPT Code

Does 90791 Require Authorization?

90791 is considered a routine outpatient appointment, so typically no authorization is required.  But like any procedure code, exceptions do exist depending on the plan and insurance company.

Some insurance companies like United Health Care (UHC) will grant one authorization for 90791 and a separate one for 90834 or 90837 EAP sessions.  If authorization is required, when you call and get authorization, make sure that 90791 is covered under it!

To find out if authorization is required, you’ll need to perform an eligibility and benefits verification on the client’s insurance plan.  We provide this service for free as part of our mental health billing service.

Does 90791 Pay More than a Normal Session?

Yes!  90791 almost always pays more per session than 90834 or 90837.

The exact payment depends on the credentialing of the provider rendering services and the insurance plan.  In our experience, 90791 is typically allowed at +35-75% of the 90834 reimbursement rate and +10-50% of the 90837 reimbursement rate.

CPT Code 90791 Time Frame

The Centers for Medicare Services (CMS.gov) requires CPT code 90791 to be 16 minutes in length at minimum and 90 minutes of length at maximum before using an add-on CPT code to designate session time.  (Source)

At TheraThink, we recommend our providers spend at least 60 minutes performing an intake session.  If a provider does need help billing their intake sessions for longer than 90 minutes, we help them by adding the appropriate add-on code to their claim.

If you are not billing your add-on codes for 90+ minute intake sessions, consider hiring us as your mental health insurance billing service to help; we are experts.

90791 Add-on CPT Codes for Time Based Billing

If the diagnostic interview lasts longer than 90 minutes, please use the following CPT codes to designate added time:

  • Add-On CPT Code +99354 — An additional 30-45 minutes of time
    • Use 90791 + 99354 if your session is between 90 and 120 minutes (1.5 to 2 hours)
  • Add-On CPT Code +99355 — An additional 45 minutes of time
    • Use 90791 + 99354 + 99355 if your session between 2-3 hours of time

If you don’t know how to bill add-on codes on your claims, consider reaching out about our mental health billing service.

How Frequently Can 90791 Be Billed for a Client?

This depends on the insurance and the plan and if you’re not sure, call the insurance. Typically Medicare and Medicaid plans allow 90791 once per client per provider per year.

Other plans will allow as frequently as once per 6 months.  Our mental health insurance billing service, TheraThink, calls to verify on your behalf to find out.

90791 vs. 90792

CPT Code 90792 is a very similar code to 90791 but there are some differences.

Like 90791, it is defined as a psychiatric diagnostic evaluation. The only distinction is that 90792 includes medical services done by a physician.

This means that only medically licensed professionals, such as a psychiatrist, can bill 90792.

CPT Code 90791 Reimbursement Rates

The following diagnostic interview reimbursement rates set by the Center for Medicare Services:

CPT Code 90791 Reimbursement Rate (2020):  $145.44

— Psychiatric diagnostic interview performed by a licensed mental health provider for 20 to 90 minutes in length.

CPT Code 90792 Reimbursement Rate (2020):  $160.96

— Psychiatric diagnostic interview performed by a psychiatrist for 20 to 90 minutes in length.

CPT Add-On Code +99354 Reimbursement Rate (2020):  $132.09

— Additional time up to 1 hour and 45 minutes for a diagnostic interview

CPT Add-On Code +99355 Reimbursement Rate (2020):  $100.33

— Additional time up to three hours for a diagnostic interview (must be used with +99354)


These 90791 reimbursement rates are set by Medicare and are national rates.  These rates are at the upper level of reimbursement for CPT Code 90791 and because Medicare is picking these rates, they are specifically for LCSWs.

If you have a different license that is not a PhD or MD, you should plan on lower rates than this from commercial insurance policies and Medicaid, in general.

Need help billing these sorts of situations?  Inquire about our mental health insurance billing service.

What License Level is Required to Bill 90791?

90791 license levelBilling for CPT Code 90791 can be performed by the following licensed mental health professionals:

  • Licensed Clinical Social Workers (LCSW)
  • Licensed Professional Counselors (LPC)
  • Licensed Mental Counselors (LMHC)
  • Licensed Marriage Family Therapists (LMFT)
  • Clinical Psychologists (PhD or PsyD)
  • Psychiatrists (MD)

If you have a different license, odds are high you are not eligible to perform a diagnostic evaluation, and as such you are not able to specify a mental health diagnosis for that client.

CPT Code 90791 Coding Requirements

The following services are required, according to Medicare, to complete an initial mental health evaluation for a new client seeking mental health services:

  • Elicitation of a complete medical and psychiatric history
  • Mental status examination
  • Evaluation of the patient’s ability and capacity to respond to treatment
  • Initial plan of treatment
  • Reported once per day
  • Not reported say day as E/M service performed by the same provider
  • Covered at the outset


Diagnostic Evaluation Documentation Requirements

Documentation should include:

  • Recording the time
  • Modality of treatment
  • Suggested frequency of treatment
  • Clinical notes that summarize:
    • Diagnosis
    • Symptoms
    • Functional status
    • Focused mental status examination
    • Treatment plan, prognosis, and progress

Documentation for CPT Code 90791 for an diagnostic evaluation must reflect a face to face meeting and this code requires a face to face meeting based on Medicare’s requirements.  (Source).