HCPCS Code A4427: Ostomy pouch drainable billing guide 2026

Key Takeaways

HCPCS Code A4427 describes an ostomy pouch, drainable, for use on a barrier with locking flange, with filter (2-piece system) – a permanent Level II HCPCS supply code that has been active since January 1, 2004

Medicare Part B covers A4427 when medically necessary following surgery that creates a permanent ostomy opening (colostomy or ileostomy), per LCD L33828

A4427 and A4426 are often confused, but both use a locking-flange barrier – the key distinction is the filter: A4427 includes a built-in filter, A4426 does not. Mixing up the filter status (or confusing either with A4425, the true non-locking filtered code) is a common claim denial trigger

Practice management software like Pabau helps practices keep the documentation trail – physician orders, diagnosis codes, delivery records – organized and audit-ready, which supports accurate ostomy supply billing, even though Pabau isn’t built as a DMEPOS-specific claims platform

HCPCS Code A4427 is a Level II Healthcare Common Procedure Coding System code used to bill Medicare, Medicaid, and commercial payers for a drainable ostomy pouch designed for use on a barrier with a locking flange and a built-in filter.

A4427 sits inside a range of near-identical ostomy codes that differ by only one or two attributes – piece count, flange type, or whether a filter is built in.

A4427 code details: Long and short description

Every HCPCS Level II code has a verbatim long description used for documentation and a condensed short description used in billing software and claim forms. For A4427, these are fixed by CMS and should be referenced exactly when submitting claims.

The filter is the significant detail in the long description. A4427 includes a built-in gas filter that vents flatus and reduces pouch ballooning, while A4426 – the otherwise identical locking-flange code – does not include one.

Both A4426 and A4427 use a locking flange, so billers should confirm whether the dispensed product has a filter, not the flange type, before choosing between the two.

A4427 fee schedule and Medicare reimbursement rates 2026

Medicare reimburses A4427 under the DMEPOS fee schedule, administered by the Centers for Medicare and Medicaid Services (CMS). Rates vary by locality and are updated annually.

The figures below reflect 2026 general Medicare allowable ranges based on available fee schedule data; verify current amounts with your DME MAC before submitting a claim.

Rate data from commercial sources like PayerPrice and HCPCSdata.com can provide directional estimates, but the authoritative source is always the CMS DMEPOS fee schedule file for the current fiscal year. Rates for 2026 should be confirmed directly before claim submission.

Medicare coverage criteria for A4427

Medicare Part B covers ostomy supplies, including the drainable pouches described by HCPCS Code A4427, when they are medically necessary per Local Coverage Determination (LCD) L33828.

Coverage is not automatic: the patient must meet specific qualifying criteria, and documentation must support those criteria before a claim is submitted. Strong patient care management processes are essential for maintaining the documentation trail.

Ostomy patients are often followed by more than one provider – the surgeon who performed the procedure, a GP office or private practice handling ongoing care, and sometimes occupational therapy support for stoma self-care training. Documentation needs to travel cleanly between all of them, not just sit with whoever placed the original order.

The core coverage requirements under LCD L33828 include:

• The patient has had surgery that created a permanent colostomy, ileostomy, or urostomy opening
• The ostomy is not expected to be closed (permanent, not temporary post-surgical ostomies)
• The supplies are ordered by the treating physician as medically necessary
• A written order from the physician is on file with the supplier before the claim is submitted
• The quantity billed does not exceed monthly quantity limits specified in the LCD
• The patient is enrolled in Medicare Part B and the supplier is an enrolled Medicare DMEPOS supplier

Coverage for non-Medicare payers varies. Medicaid programs differ by state, and commercial payers have their own medical necessity criteria. Always verify plan-specific requirements before submitting claims to non-Medicare payers.

Billing guidelines and documentation requirements for A4427

Incomplete documentation is the leading cause of A4427 claim denials. CMS and DME MAC auditors look for specific records before approving payment. Using digital intake forms and structured documentation workflows reduces the risk of missing required elements at the time of claim submission.

Required documentation for A4427 claims typically includes:

• Standard Written Order (SWO): a signed and dated order from the treating physician specifying the product type, quantity, and frequency for ongoing supplies. CMS replaced the Detailed Written Order (DWO) with the SWO for all DMEPOS effective January 1, 2020 (Final Rule CMS-1713), so claims should reference an SWO, not a DWO
• Medical records confirming the surgical procedure that created the ostomy (operative report or discharge summary)
• Diagnosis code(s) supporting medical necessity, submitted alongside the HCPCS code on the claim
• Proof of delivery: beneficiary signature confirming receipt of supplies
• KX modifier: appended to A4427 when the supplier attests that documentation on file meets Medicare coverage criteria

Billers should also note that Medicare imposes per-month quantity limits on ostomy supplies. The specific limits are defined in LCD L33828 and its related Policy Article. Exceeding those limits without prior authorization or a documented medical justification will result in denial.

For comprehensive HCPCS claims workflow guidance, the AAPC Codify HCPCS lookup provides billing tips, payer-specific notes, and related code cross-references alongside the code description.

Ostomy pouch types: Colostomy, ileostomy, and urostomy coding

Selecting the correct HCPCS code depends on both the type of ostomy and the product design. A4427 applies specifically to drainable pouches used with locking-flange barriers. Understanding which code fits which ostomy type prevents mis-billing and reduces denial rates.

Accurate medical forms documentation at intake should capture the ostomy type and barrier system in use.

A4427 does not apply to urostomy pouches. Urostomy drainage requires codes in the A4428-A4432 range, which describe pouches designed specifically for urinary output with different barrier and faucet-type tap configurations.

A4427 vs A4426: Understanding the difference

This is one of the most common coding confusions in ostomy supply billing, but not for the reason many billers assume. A4426 and A4427 both describe drainable ostomy pouches for use with a two-piece, locking-flange barrier system – the flange type is the same for both codes.

The sole differentiator is the filter: A4427 includes a built-in gas filter, and A4426 does not. The true non-locking, filtered counterpart to A4427 is a separate code, A4425, not A4426.

Before billing A4427, confirm from the product specification sheet that the pouch includes a built-in filter. Both A4426 and A4427 use a locking-flange barrier, so the locking mechanism itself does not distinguish the two codes.

Submitting A4427 for a product with no filter constitutes a coding error and creates audit exposure. The product manufacturer’s literature or the PDAC (Pricing, Data Analysis and Coding) contractor can verify HCPCS code assignments for specific products.

Related HCPCS codes for ostomy supplies

The A4420-A4435 range covers the full spectrum of ostomy pouch and barrier codes. Billers managing multiple ostomy patients need to navigate this range accurately. The table below covers the codes most frequently billed alongside or instead of A4427. For a complete code listing with payer notes, the PGM HCPCS lookup provides free CMS-sourced data.

Billers handling a full DME supply catalog also run into codes well outside the ostomy family. J1040 follows the same documentation discipline: a signed order, a diagnosis code, and delivery proof on file before submission.

How to bill HCPCS Code A4427 in practice management software

Accurate claim submission for A4427 requires more than selecting the correct code. Billers need to configure their practice management software to capture the diagnosis code, physician order, and delivery confirmation that payers require. Missing any one of these is what causes most ostomy supply claims to fail at first submission.

A well-configured billing workflow for A4427 follows this sequence:

1. Capture the diagnosis code at intake: Record the ICD-10-CM code for the ostomy condition (e.g., Z93.3 for colostomy status). This links to A4427 on the claim and supports medical necessity. Practice management software like Pabau can store this pairing in a saved documentation template, so front-desk staff capture it the same way at every visit.
2. Attach the KX modifier: For Medicare claims, append modifier KX to A4427 when documentation on file meets LCD L33828 criteria. Missing the KX modifier is a top denial trigger for DMEPOS supply codes.
3. Set the correct place of service: Ostomy supplies billed under DMEPOS typically use place of service 12 (home) or 99 (other/unlisted). Confirm with your DME MAC if the patient receives supplies at a facility versus at home.
4. Verify quantity against LCD limits: The billing system should flag when the quantity billed approaches or exceeds the monthly limit specified in LCD L33828. Build in a pre-submission edit check for this.
5. Attach proof of delivery before final submission: Claims submitted without proof of delivery, a valid Standard Written Order (SWO), or supporting medical record documentation on file are vulnerable to post-payment audit recoupment, even when initially paid. Ostomy supplies were never on the CMN/DIF list, and CMS eliminated the remaining CMN/DIF requirements for dates of service on or after January 1, 2023 – auditors will ask for the SWO and medical record, not a CMN.

Modern practice management software features including automated claim scrubbing, modifier validation, and quantity limit alerts significantly reduce the manual oversight burden for high-volume DMEPOS billing.

The same intake discipline extends well past ostomy claims – a diagnosis code like L26 needs capturing at the same visit, not backfilled later. Reviewing your system’s HCPCS supply code configuration against current LCD requirements at the start of each benefit year is good practice.

Keep ostomy billing documentation audit-ready with Pabau

Practice management software like Pabau helps practices capture physician orders, diagnosis codes, and treatment records in one place, so the documentation behind every ostomy supply claim is organized and easy to produce during an audit.

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Conclusion

HCPCS Code A4427 is straightforward in principle but easy to mis-bill in practice. The filter-vs-no-filter distinction separates it from A4426 (both use a locking flange), the urostomy exclusion rules out A4428-A4432, and the documentation requirements under LCD L33828 determine whether a claim pays or denies.

Pabau brings together the documentation capture and record-keeping – physician orders, diagnosis codes, treatment notes – that support accurate ostomy supply billing, even though it’s built for general practice management rather than DMEPOS-specific claims processing. To see how it fits your practice’s documentation workflow, book a demo.

Continue your research

Need to document patient conditions that support A4427 claims? HIPAA compliance for medical offices covers documentation standards that protect both patient records and audit readiness.

Handling other DME supply codes alongside ostomy claims? A4326 is the billing guide for male external catheters, another commonly confused DMEPOS supply code.

Looking for a broader HCPCS billing reference? Billing code reference guides on Pabau cover procedure and supply code documentation across specialties.

Frequently asked questions