CPT
90471 — Immunization administration, single vaccine
ACA-covered vaccines should be free, including the admin fee.
Mental health
90791 — Psychiatric diagnostic evaluation without medical services
This is the initial comprehensive psychiatric evaluation for a new patient that does not include a physical exam or medication management — it covers the history, mental status exam, diagnosis, and treatment planning.
- Typical setting: Therapist's office, hospital, telehealth
- National avg charge (illustrative): $150–$350 (Medicare national non-facility rate approximately $179 in 2026)
- Most-disputed reason: Billing 90791 more than once for the same patient within the same treatment episode without documentation of a significant change in mental status or an extended break in care (approximately 6 months).
What it means
What 90791 actually means
This is the initial comprehensive psychiatric evaluation for a new patient that does not include a physical exam or medication management — it covers the history, mental status exam, diagnosis, and treatment planning. Typically performed by therapists, psychologists, and psychiatrists when no medication prescribing occurs.
Common errors with this code
What goes wrong on real bills.
Most bills that look correct still contain at least one of these issues. Up to 49% of medical bills contain errors (CFPB).
- Billing 90791 more than once for the same patient within the same treatment episode without documentation of a significant change in mental status or an extended break in care (approximately 6 months).
- Billing 90791 for what was actually an established-patient follow-up visit — this code is for initial diagnostic evaluations, not routine therapy check-ins.
- A psychiatrist billing 90791 when the evaluation included medication prescribing or a physical exam component — those services require 90792 instead.
If you see 90791 on your bill
Three steps before paying.
1. Get the itemized bill. If your statement only shows a summary, request the CPT-level itemized bill before paying. Generate the request language →
2. Cross-check against the EOB. Compare what your insurer's Explanation of Benefits says you owe versus what the hospital is asking. They disagree more often than people think. Read the bill-vs-EOB guide →
3. Run a free Bill Scan. Upload the bill (and EOB if you have it) and BillBusted will flag the most likely issues with this specific code in your specific state. Run free scan →
Related codes
Other codes in this category.
People who land on 90791 often also see these adjacent codes on the same bill.
CPT
90472 — Immunization admin; each additional vaccine
Vaccine — admin (90471) is separate from the vaccine product code.
CPT
90651 — Human papillomavirus vaccine types 6, 11, 16, 18, 31, 33, 45, 52, 58, nonavalent , IM
Vaccine — admin (90471) is separate from the vaccine product code.
CPT
90670 — Pneumococcal conjugate vaccine, 13 valent , IM
Vaccine — admin (90471) is separate from the vaccine product code.
CPT
90671 — Pneumococcal conjugate vaccine, 15 valent , IM
Vaccine — admin (90471) is separate from the vaccine product code.
CPT
90677 — Pneumococcal conjugate vaccine, 20 valent , IM
Vaccine — admin (90471) is separate from the vaccine product code.
Related BillBusted guides
Plain-English reads if you see 90791 on a bill.
90791 FAQ
Plain-English answers.
What does 90791 usually cost?
$150–$350 (Medicare national non-facility rate approximately $179 in 2026). Costs vary by region, payer contract, and whether the service was performed in a hospital outpatient department (which adds a facility fee) versus a free-standing clinic.
What's the most common billing error on 90791?
Billing 90791 more than once for the same patient within the same treatment episode without documentation of a significant change in mental status or an extended break in care (approximately 6 months).
What should I do if I see 90791 on my bill?
Request the itemized bill and the matching EOB from your insurer. Compare the units/quantity billed against what you actually received. Run a free BillBusted scan to flag the most likely errors specific to 90791 before paying.
Don't pay 90791 blindly.
The free scan tells you in under 60 seconds whether this charge looks reasonable for your situation.