HCPCS
A0021 — Ambulance service, outside state per mile, transport (medicaid only)
Outside state ambulance serv
Medical / surgical supplies, transport
A4372 — Ostomy skin barrier, solid 4 x 4 or equivalent, standard wear, with built-in convexity, each
HCPCS code A4372 is used on U.S. medical bills for medical / surgical supplies, transport: Ostomy skin barrier, solid 4 x 4 or equivalent, standard wear, with built-in convexity, each.
- Typical setting: Outpatient or transport
- National avg charge (illustrative): Allowed amount varies by region — check Medicare fee schedules or your plan's allowed amount.
- Most-disputed reason: Units of service overstated
What it means
What A4372 actually means
Ostomy skin barrier, solid 4 x 4 or equivalent, standard wear, with built-in convexity, each.
The official CMS HCPCS Level II descriptor for this code is shown above. If the description on your bill does not match the service you actually received, that is a reason to ask for the itemized bill and dispute the line.
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).
- Quantity or units of service that exceed what the medical record supports.
- Duplicate billing on the same date of service.
- Missing or incorrect modifier (e.g., JW for drug waste, RT/LT for sides).
- Units of service overstated without supporting documentation.
If you see A4372 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 A4372 often also see these adjacent codes on the same bill.
HCPCS
A0080 — Non-emergency transportation, per mile - vehicle provided by volunteer (individual or organization), with no vested interest
Noninterest escort in non er
HCPCS
A0110 — Non-emergency transportation and bus, intra or inter state carrier
Nonemergency transport bus
HCPCS
A0120 — Non-emergency transportation: mini-bus, mountain area transports, or other transportation systems
Noner transport mini-bus
Related BillBusted guides
Plain-English reads if you see A4372 on a bill.
A4372 FAQ
Plain-English answers.
What is A4372 used for on a medical bill?
HCPCS code A4372 is used on medical bills for medical / surgical supplies, transport: Ostomy skin barrier, solid 4 x 4 or equivalent, standard wear, with built-in convexity, each. Up to 49% of medical bills contain at least one error (CFPB, 2023), and codes in this category most often get flagged for units of service overstated. If you see A4372 on your bill, request the itemized statement and compare the units, date of service, and description to your Explanation of Benefits before paying.
How much should A4372 cost?
How much A4372 should cost depends on your payer and region. Up to 49% of medical bills contain at least one error (CFPB, 2023), and pricing for this HCPCS code is set by Medicare fee schedules for Medicare claims and by negotiated allowed amounts for commercial plans. Check the Medicare fee-schedule lookup tool, your insurer's member portal, or run a free BillBusted scan to compare your charge against typical allowed amounts.
Can I dispute a A4372 charge on my medical bill?
Yes, you can dispute a A4372 charge on your medical bill if the units, modifier, date of service, or coverage doesn't match the medical record or your insurance benefits. About 73.7% of patients who actually dispute a medical bill receive a correction (JAMA Health Forum, 2024). Request the itemized bill, compare to your EOB, and use BillBusted's Resolution Pack to draft the dispute letter if needed.
Don't pay A4372 blindly.
The free scan tells you in under 60 seconds whether this charge looks reasonable for your situation.