HCPCS code A4429 – Convex urinary ostomy pouch

Key takeaways

HCPCS code A4429 bills one one-piece urinary ostomy pouch with an attached barrier, built-in convexity and a faucet-type drain tap.

Convexity separates A4429 from A4431, and an extended wear barrier moves a convex one-piece urinary pouch to A4430.

Medicare covers ostomy supplies as prosthetic devices under Social Security Act section 1861(s)(8), following LCD L33828 and policy article A52487.

LCD L33828 sets the usual maximum for A4429 at 20 pouches a month, and a higher quantity needs support in the medical record.

Policy article A52487 lists only two urinary diagnosis codes, Z93.6 and Z43.6, so cystostomy codes Z93.50 to Z93.59 do not support the claim.

What is HCPCS code A4429?

HCPCS code A4429 is the Level II code for a one-piece urinary ostomy pouch with an attached barrier, built-in convexity and a faucet-type tap. Suppliers bill it per pouch to the DME MAC under the Medicare ostomy supplies policy.

The official long descriptor reads: Ostomy pouch, urinary, with barrier attached, with built-in convexity, with faucet-type tap with valve (1 piece), each. Check the wording against the CMS HCPCS Level II code file when each annual update is released.

What each part of the descriptor means

• Urinary: the pouch collects urine from a urostomy. Policy article A52487 notes that a urinary pouch normally has anti-reflux features and a tap or spigot for emptying.
• Barrier attached (1 piece): the adhesive skin barrier is part of the pouch, so the patient removes the whole appliance at each change.
• Built-in convexity: the barrier curves outward to press gently on the skin around the stoma. Clinicians often choose it for a flush or retracted stoma, but the code describes the product rather than the stoma.
• Faucet-type tap with valve: a small valve at the base lets the patient drain urine without taking the pouch off.
• Each: one unit of service is one pouch.

The descriptor leaves out wear time, and that omission matters. A convex one-piece urinary pouch with an extended wear barrier is A4430, not A4429.

A4429 vs related urinary pouch codes

The urinary pouch codes run from A4428 to A4434. Three features separate them: the barrier wear rating, built-in convexity, and whether the system is one-piece or two-piece. Drainable pouches for a colostomy or ileostomy, such as A4424 to A4427, are a separate family, so a urostomy pouch never belongs there.

Three questions settle the code. First, is the barrier part of the pouch? If it is not, the system is two-piece and belongs to A4432, A4433 or A4434.

Second, does the attached barrier have built-in convexity? A flat barrier points to A4428 or A4431, and a convex one points to A4429 or A4430. Third, is that convex barrier rated extended wear? If so, the pouch is A4430. If not, it is A4429.

Two convex pouches can look alike on a packing list and still carry different codes. Read the manufacturer’s HCPCS coding statement for the exact product before the first claim.

Medicare coverage for HCPCS code A4429

Medicare Part B covers A4429 under the prosthetic device benefit in Social Security Act section 1861(s)(8). It is not covered as durable medical equipment under section 1861(s)(6), even though the DME MACs process the claims.

Coverage follows LCD L33828 (Ostomy Supplies) and its companion policy article A52487. All four DME MAC jurisdictions apply the same policy.

An A4429 claim meets the coverage criteria when these points hold:

• The beneficiary has a surgically created stoma that diverts urine.
• The condition is permanent, meaning the medical record shows it will last a long and indefinite time.
• The pouch dispensed matches every element of the A4429 descriptor.
• A standard written order from the treating practitioner reaches the supplier before the claim is billed.
• The quantity stays within the usual maximum, or the medical record explains why more is needed.

Quantity limits for A4429

LCD L33828 sets the usual maximum for A4429 at 20 pouches per month. The LCD ties quantity to the type of ostomy, its location and construction, and the condition of the skin around the stoma.

A higher quantity needs a clear explanation in the medical record. Units above 20 without that support are denied as not reasonable and necessary.

Shipment size is capped as well. A nursing facility resident may receive one month of supplies at a time. A beneficiary at home may receive up to three months.

Prior authorization requirements

Medicare Part B does not require prior authorization for A4429. Other payers set their own rules, so confirm each one before you dispense.

ICD-10-CM codes that support A4429 claims

Policy article A52487 lists ten ICD-10-CM codes that support medical necessity for ostomy supplies. Only two describe a urinary diversion, and those are the codes an A4429 line carries.

The policy article also states that a listed code alone does not assure coverage. The underlying condition does not belong on the line by itself either. Bladder cancer, for example, is absent from the list, so a claim that carries only C67.9 invites a medical necessity denial.

Documentation requirements for A4429 claims

Every A4429 claim rests on records that a DME MAC reviewer can follow without follow-up questions. A structured billing compliance routine keeps these items in the supplier’s file:

• Standard written order (SWO): it names the beneficiary, the order date, the item and the quantity. It also carries the treating practitioner’s name or NPI and signature.
• Order timing: the SWO must reach the supplier before the claim is submitted.
• Medical record support: the practitioner’s notes show the urinary stoma, its permanence, and the reason for any quantity above 20 a month.
• Covered diagnosis: Z93.6 or Z43.6 from the policy article’s list.
• Continued need and use: a record that the stoma is still present and the pouches are still in use.
• Proof of delivery: a signed receipt or shipping record, kept for seven years.

Ostomy supplies need no Certificate of Medical Necessity. CMS retired CMNs and DME information forms for claims with dates of service on or after January 1, 2023.

Refill rules for recurring shipments

• Contact the beneficiary or their designee no sooner than 30 calendar days before the current supply is expected to run out.
• Record an affirmative response. Shipping on a fixed schedule without that response is not allowed.
• Deliver no sooner than 10 calendar days before the current supply is expected to run out.

Medicare fee schedule and payment for A4429

Medicare pays A4429 from the CMS DMEPOS fee schedule, not the Physician Fee Schedule. The code carries no relative value units, so a physician fee schedule lookup shows no rate for it.

Allowed amounts are published by state, with rural and non-rural columns, and CMS updates the file each quarter. The beneficiary’s permanent residence decides which amount applies.

• A4429 is a purchase-only disposable supply, so rental rules do not apply.
• Medicare Part B pays 80% of the allowed amount once the annual deductible is met.
• Ostomy supplies are not separately payable during a covered home health episode, because the agency furnishes them.

No competitive bidding contract covers ostomy supplies today. CMS’s November 2025 final rule adds ostomy supplies to the next round as remote item delivery contracts, currently expected to start in 2028.

How to bill A4429 step by step

The steps below follow the standard DME MAC workflow for a Medicare Part B claim.

1. Confirm the product. Check that the pouch is one-piece, has an attached convex barrier that is not extended wear, and drains through a faucet-type tap.
2. Get the SWO on file. It must name the item and quantity and carry the treating practitioner’s signature.
3. Assign the diagnosis. Use Z93.6 for urinary stoma status, or Z43.6 for an encounter focused on the stoma.
4. Count the units. Bill one unit per pouch and stay at or under 20 for the month, unless the record explains more.
5. Keep the barrier off the claim. The barrier is part of the A4429 unit, so no separate skin barrier line goes out for the same appliance.
6. Submit to the DME MAC. Use the CMS-1500 or 837P format for the beneficiary’s jurisdiction, with place of service 12 for delivery to the home.
7. Work the remittance. File within one calendar year of the date of service, and read each reason code on the remittance advice.

Modifiers used with A4429

LCD L33828 and policy article A52487 set no KX modifier requirement for ostomy pouches, so a claim is not denied for leaving KX off. The only modifier the policy article names is AU, and it applies to three accessory codes rather than to A4429.

Common reasons A4429 claims are denied

Most A4429 denials come from a short list of preventable errors. A steady denial management process catches them before the claim goes out.

The reason codes on the remittance advice point to the specific error. Map them with this guide to denial codes in medical billing before you correct and resubmit.

How to appeal a denied A4429 claim

Medicare fee-for-service appeals run through five levels. Most A4429 appeals end at the first level, once the missing order, diagnosis or refill record is supplied.

1. Redetermination (level 1): ask the DME MAC within 120 days of receiving the initial determination.
2. Reconsideration (level 2): ask a Qualified Independent Contractor within 180 days of the redetermination decision.
3. Administrative law judge hearing (level 3): request it within 60 days of the reconsideration decision, when the amount in controversy meets the annual threshold.
4. Medicare Appeals Council review (level 4): request it within 60 days of the hearing decision.
5. Judicial review in federal district court (level 5): file within 60 days of the Council decision, when the amount meets the higher annual threshold.

Track each deadline per claim. A missed filing window forfeits the appeal at that level.

How Pabau keeps urinary ostomy pouch claims audit-ready

An A4429 claim draws on records that often sit in different places. The order arrives by fax, delivery receipts live in the shipping system, and refill calls get noted wherever the caller had a screen open.

Pabau, the practice management and billing platform we build, keeps those records on one patient file. The signed order, intake forms, clinical notes and diagnosis sit together, so pulling a year of documentation for a review takes one search.

Pabau’s claims management software sends each claim and tracks its status through to the remittance. A denial shows up while the refill cycle is still open, so you fix the record before the next shipment.

Keep urinary ostomy pouch claims audit-ready

Pabau keeps orders, diagnoses and refill records on one patient file and tracks each claim to payment, so denials surface before the next shipment.

Book a demo

Conclusion

The pouch in hand and its manufacturer’s coding statement settle the code. A one-piece urinary pouch with a convex barrier that is not extended wear is A4429. Make that barrier extended wear and the code becomes A4430, and flatten it and the code becomes A4431.

Pair the line with Z93.6 or Z43.6, keep to 20 pouches a month unless the record explains more, and log each refill request. A claim built that way rarely reaches an appeal. Book a demo to see how Pabau keeps urinary ostomy supply orders, records and claims on one patient file.

Continue your research

Need to understand the full medical billing picture? What is medical billing covers the end-to-end revenue cycle workflow from patient encounter to payment posting.

Dealing with recurring claim rejections? Denial management in healthcare explains how to build a structured denial resolution process that reduces re-submission time.

Want to strengthen your DMEPOS compliance posture? Medical billing compliance outlines the documentation and audit-readiness standards that protect suppliers from recoupment.

Coding a flat-barrier pouch instead? HCPCS code A4428 covers the one-piece urinary pouch with an extended wear flat barrier.

Is the barrier a separate piece? HCPCS code A4432 explains how two-piece urinary pouches on a non-locking flange are billed.

Frequently asked questions