CPT
90471 — Immunization administration, single vaccine
ACA-covered vaccines should be free, including the admin fee.
Preventive care
99391 — Preventive medicine, established patient; infant younger than 1 year
This code covers a well-child visit for an established patient under 1 year of age — meaning the child has been seen by a provider in the practice within the past 3 years.
- Typical setting: Doctor's office
- National avg charge (illustrative): $110-$205 (commercial/Medicaid)
- Most-disputed reason: New vs. established error: billing 99391 for a truly new patient — should be 99381
What it means
What 99391 actually means
This code covers a well-child visit for an established patient under 1 year of age — meaning the child has been seen by a provider in the practice within the past 3 years. It includes the same components as the new-patient code (99381) but is reimbursed at a slightly lower rate because the provider already has a baseline history.
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).
- New vs. established error: billing 99391 for a truly new patient — should be 99381
- Age bracket error: billing 99391 when the child has turned 1 — use 99392 for ages 1-4
- Vaccine administration billing error: bundling vaccine administration fees into the E/M code instead of billing them separately with the appropriate administration codes (90460-90461)
If you see 99391 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 99391 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 99391 on a bill.
99391 FAQ
Plain-English answers.
What does 99391 usually cost?
$110-$205 (commercial/Medicaid). 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 99391?
New vs. established error: billing 99391 for a truly new patient — should be 99381
What should I do if I see 99391 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 99391 before paying.
Don't pay 99391 blindly.
The free scan tells you in under 60 seconds whether this charge looks reasonable for your situation.