CPT
90471 — Immunization administration, single vaccine
ACA-covered vaccines should be free, including the admin fee.
Inpatient hospital care
99231 — Subsequent hospital inpatient/observation care, low complexity (25+ min)
Daily follow-up E/M after the admission day. 99231 is the lowest of three levels — for a stable patient who is recovering as expected.
- Typical setting: Hospital inpatient or observation
- National avg charge (illustrative): Insurance allowed $48–$70; physician-side, per day.
- Most-disputed reason: Two providers from the same specialty billing on the same day.
What it means
What 99231 actually means
CPT 99231 is the lowest of three subsequent hospital care levels (99231, 99232, 99233). It applies to a stable, recovering patient with straightforward decision-making, or a 25-minute encounter. One of these codes should appear for each hospital day after admission.
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).
- Two physicians from the same specialty in the same group both billing 99231 for the same patient on the same day — Medicare typically pays only one.
- Billed for a day the physician didn't actually see the patient (e.g., handoff days, weekends with cross-coverage that wasn't separately documented).
- Upcoded to 99232 or 99233 when the patient is actually stable.
If you see 99231 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 99231 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 99231 on a bill.
99231 FAQ
Plain-English answers.
How do I know if a daily 99231 charge is real?
Request the daily progress notes from your medical record. Each billed day should have a dated, signed progress note from the billing physician documenting the visit. Days with no note (or only a nurse's note) are disputable.
Don't pay 99231 blindly.
The free scan tells you in under 60 seconds whether this charge looks reasonable for your situation.