HCPCS code A4358: Urinary drainage bag billing guide

Key Takeaways

HCPCS code A4358 describes a urinary drainage bag, leg or abdomen, vinyl, with or without tube, with straps, each, a Level II HCPCS supply code for DME billing.

Medicare Part B covers A4358 under LCD L33803 with a routine quantity limit of up to two bags a month; more requires documented medical necessity such as infection, obstruction, or clotting.

KX confirms documentation is on file when LCD criteria are met, not a modifier required on every claim; GA or GZ apply instead when coverage is expected to be denied.

Practice management software like Pabau checks that a claim’s required fields are complete before it’s sent, gates submission until they are, and shows claim status on one dashboard.

HCPCS code A4358 is the vinyl urinary leg or abdomen drainage bag, with the tube and straps built into the same code. It’s a routine DME billing code, but three things trip suppliers up every month: an outdated descriptor, a quantity limit that gets misquoted, and a modifier applied out of habit instead of documentation.

Get those three right and the rest of the claim tends to fall into place, starting with what the code actually describes.

What HCPCS code A4358 actually covers

The CMS descriptor for A4358 is: Urinary drainage bag, leg or abdomen, vinyl, with or without tube, with straps, each. It’s a Level II HCPCS supply code maintained by CMS and updated annually, sitting inside the A4310-A4360 incontinence devices and supplies range alongside external catheters and related urological items billed to Medicare Part B as durable medical equipment (DME).

The “with or without tube” part of the descriptor is intentional. A single code covers bags sold with or without attached tubing, so coders don’t need to hunt for a different code over that one accessory. The straps that hold the bag in place are already priced into A4358, they aren’t billed as a separate item (more on that in the FAQ below).

A4358 at a glance: The code details billers need

The table below captures the key administrative facts coders need before billing A4358.

Note that A4358 covers only vinyl bags worn on the leg or abdomen. The latex version, night drainage bags, and replacement leg straps all have their own codes in the same range, covered in the FAQ below and the Related Codes section further down.

Does Medicare cover HCPCS code A4358, and under what conditions?

Medicare Part B covers HCPCS A4358 under Local Coverage Determination L33803 (Urological Supplies), administered by the DME Medicare Administrative Contractors (DME MACs).

The claim has to meet the criteria in LCD L33803, and since A4358 isn’t on Medicare’s Written-Order-Prior-to-Delivery list, the supplier can dispense the bag on a verbal order but needs a complete Standard Written Order (SWO) on file before the claim goes out.

What LCD L33803 requires before you can bill A4358

Medicare covers A4358 when all of the following are met:

• The beneficiary has a permanent or long-term urinary incontinence or retention condition requiring an indwelling catheter or external catheter connected to a drainage bag.
• A written order from the treating physician documents the medical necessity of the urinary drainage bag.
• The diagnosis supporting necessity is one of the ICD-10-CM codes listed in LCD L33803 (see the ICD-10 section below).
• The supplier is an enrolled Medicare DMEPOS supplier with a valid supplier number.

How many bags can you actually bill in a month?

The routine Medicare quantity limit for A4358 is up to two bags a month. That covers scheduled changes.

Going beyond it takes documentation showing why, an infection, obstruction, sludging, or clotting that forces an unscheduled swap, not just a preference for a fresh bag. Quantities get checked at adjudication, so a claim over the routine allowance without that documentation and the right modifier gets denied.

Verify the exact limit with your DME MAC before billing. Two contractors cover all four DME MAC jurisdictions between them: Noridian Healthcare Solutions runs Jurisdictions A and D, and CGS Administrators runs Jurisdictions B and C. Either can publish a policy article that clarifies or adds to the national LCD.

What Medicare actually pays for A4358 under the 2026 fee schedule

Medicare reimbursement for A4358 is set through the annual DMEPOS fee schedule published by CMS. Rates are adjusted for geographic locality using the Fee Schedule Area (FSA) corresponding to the beneficiary’s permanent residence, not the supplier location.

The 2026 national average Medicare fee for A4358 was not available from a verified primary source at time of writing. Always confirm the current rate directly from the CMS fee schedule lookup tool before billing, as rates change each January 1. Using a stale rate from a third-party aggregator risks underbilling or triggering a payment discrepancy audit.

Suppliers participating in the CMS DMEPOS Competitive Bidding Program may receive contract amounts that differ from the published fee schedule rate. Check with your DME MAC to confirm whether your service area falls under a competitive bidding arrangement for urological supplies.

Which ICD-10 codes make an A4358 claim stick

Every A4358 claim requires a supporting ICD-10-CM diagnosis code that establishes medical necessity under LCD L33803. Submitting without a covered diagnosis code, or pairing A4358 with a non-covered code, is one of the most common reasons these claims are denied on initial submission.

Pelvic health practices and urology practices bill this code constantly, right alongside catheter and incontinence supply codes, so getting the paired diagnosis right matters.

The table below lists the primary ICD-10-CM codes that CMS and DME MACs accept as establishing medical necessity for urinary drainage bags. Verify current codes against the active LCD version, as ICD-10 code sets update annually on October 1.

Always confirm the full covered and non-covered code lists in the active version of LCD L33803 via the CMS Medicare Coverage Database. Codes that appear covered under a prior LCD version may have been removed in subsequent updates.

Documentation: what has to be on file before you bill

Inadequate documentation is the single biggest driver of A4358 post-payment audits. The DME MAC wants a specific set of documents on file at the time of billing, not assembled after a request letter arrives.

A gap in any one of them gives the MAC grounds for recoupment. Good medical forms and documentation workflows make that closer to automatic than manual.

• Standard Written Order (SWO): A4358 isn’t on Medicare’s Written-Order-Prior-to-Delivery list, so a supplier can dispense the bag on a verbal or preliminary order. A complete SWO, meeting CMS’s required elements and signed by the treating physician, has to be on file before the claim goes out. The CMN and DWO forms this used to run through were retired for DME claims on January 1, 2023.
• Medical records: Supporting clinical notes from the treating physician documenting the diagnosis, symptoms, and why alternative management is insufficient.
• Proof of delivery: Supplier must retain a delivery receipt signed by the beneficiary or authorized representative, showing item name, date, and quantity delivered.
• Quantity justification (if above the routine limit): Billing more than two bags a month needs added physician documentation explaining the clinical rationale, kept on file alongside the rest of the claim record.

Maintaining HIPAA documentation requirements isn’t optional in DME billing. CMS auditors routinely request the full file, and a missing item means recoupment regardless of whether the clinical need was genuine.

Digital intake forms capture physician orders and patient acknowledgment at the point of care, in a format you can actually retrieve later.

Before you submit: a quick A4358 checklist

• Complete SWO on file, signed by the treating physician.
• ICD-10-CM code from the covered list in LCD L33803.
• Proof of delivery signed by the beneficiary or authorized representative.
• Quantity matches the routine two-bags-a-month allowance, or extra documentation is attached for anything above it.
• Modifier (KX, GA, or GZ) matches what the documentation on file actually supports.

How an A4358 claim moves from order to payment

Here is the order things actually happen in, from the physician’s office to a paid claim:

1. The treating physician, often a GP practice managing a patient’s long-term incontinence, documents medical necessity and either signs a complete SWO or gives a verbal order the supplier follows up on before billing.
2. The DME supplier, enrolled with Medicare and holding a valid supplier number, dispenses the bag and collects proof of delivery signed by the beneficiary.
3. The biller attaches the covered ICD-10-CM code, picks KX, GA, or GZ based on what the file actually supports, and submits to the correct DME MAC jurisdiction.
4. The DME MAC adjudicates against LCD L33803, checking the quantity billed against the routine two-bags-a-month allowance and the modifier against the documentation on file, before paying, holding, or denying the claim.

Modifiers: How to pick KX, GA, or GZ correctly

Correct modifier use on A4358 claims directly determines whether Medicare pays, holds, or denies the claim. Three modifiers govern most A4358 submissions.

Using the wrong one signals a coverage status to the MAC that does not match your documentation, which triggers a denial or an Advanced Beneficiary Notice (ABN) liability issue.

The KX modifier is the default for routine A4358 claims once your file backs it up. Attach it when the record includes a complete SWO, a supporting ICD-10 diagnosis, and proof of delivery. Applying GA or GZ to a claim that’s actually covered is a coding error, not a cautious choice.

Keeping paperless billing records current keeps signed ABNs, delivery records, and physician orders on hand for both modifier decisions and post-payment review.

Worked example: a supplier dispenses two A4358 bags in March under a documented UTI-driven change, with a complete SWO and ICD-10 code N39.41 on file. That claim goes out with KX. A different patient wants a third bag the same month with no documented reason beyond wanting a spare, and no ABN was issued before the supplier shipped it anyway. That claim should carry GZ, and the supplier, not the patient, absorbs the cost if Medicare denies it.

Additional billing rules to observe:

• Bill one unit per bag supplied. The quantity billed should match what’s actually dispensed, up to the routine two-bags-a-month allowance covered above.
• The supplier must be an enrolled Medicare DMEPOS supplier. Physicians cannot bill A4358 directly to Medicare Part B.
• For HIPAA-compliant practice software environments, retain all A4358 claim records for the minimum required period (seven years for Medicare claims).
• Verify coding guidance with your specific DME MAC. Only two contractors administer all four DME MAC jurisdictions: Noridian Healthcare Solutions (Jurisdictions A and D) and CGS Administrators (Jurisdictions B and C). Either can publish rules beyond the national LCD. The CGS coding guidance page covers MAC-specific DMEPOS supply coding.

Get A4358 claims out clean, not bounced back

Practice management software like Pabau checks that a claim’s required fields are complete before it is sent, gates submission until they are, and shows claim status on one dashboard instead of a spreadsheet.

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Where A4358 fits among the A4310-A4360 codes

A4358 is one of several urological supply codes in the A4310-A4360 range. Selecting the wrong adjacent code is a common audit trigger: each code has a specific product configuration, and billing A4358 for a product that belongs under A4354 or A4356 creates a mismatch between the claim and the delivery documentation.

Quick question: can you bill A4358 and a catheter insertion tray in the same month? Quick answer: only if the tray code doesn’t already bundle a bag. Check the tray’s own descriptor (A4310, A4311, A4314) before adding A4358 to the same claim.

When a patient receives both a catheter kit and a separate drainage bag in the same month, check whether the catheter kit code already bundles a bag. If it does, billing A4358 separately creates an unbundling issue.

Review the full HCPCS Level II code range with the AAPC code lookup to confirm component relationships before you submit. Pabau’s procedure codes hub has the rest of the CPT and HCPCS billing guides for more context.

Common mistakes that trigger an A4358 denial

• Billing more than two bags a month without documented medical necessity attached.
• Defaulting to KX out of habit instead of checking the file actually supports it.
• Naming Noridian, CGS, National Government Services, and Palmetto as the four A4358 contractors, only Noridian and CGS administer this jurisdiction range.
• Treating the CMN/DWO framework as current; Medicare retired those forms for DME claims on January 1, 2023, in favor of the SWO.
• Billing A4358 separately when the patient’s catheter kit code (A4311 or A4314) already bundles a drainage bag.

Where practice management software actually helps with A4358 billing

DME billing teams juggling A4358 claims by hand keep hitting the same wall: the documentation package isn’t complete when the claim is ready to go, and nobody catches it until the payer bounces it back. That’s the specific problem the right practice management software closes.

Pabau’s claims management software checks that the fields a payer actually needs are filled in, then gates the send button until they are. Nothing goes out half-finished, and a claim’s status, pending, submitted, processing, paid, or flagged as an error, sits on one dashboard instead of a string of phone calls to the payer.

• Required fields checked before send: a claim can’t leave the building missing the diagnosis code, order details, or delivery information a payer needs to process it.
• One dashboard for status: pending, submitted, processing, paid, or flagged, at a glance, instead of chasing a payer by phone to find out where a claim sits.
• Documents live with the patient record: the SWO and delivery paperwork collected during the visit sit on the same patient file the biller works from, no separate request needed.
• One system, not five: DME billing sits next to scheduling, records, and payments in the same platform, so a biller isn’t switching tools to build a claim for a leg bag, a walker like E0130, or crutches like E0114.

The bottom line on A4358 claims

A4358 denials almost always trace back to the same three things: documentation that isn’t actually on file, a modifier that doesn’t match it, or a diagnosis code the LCD doesn’t recognize. All three are preventable with the checklist earlier in this guide and a quick MAC verification before you submit.

Pabau won’t pick your modifier or write your SWO for you, but it will stop a claim that’s missing a required field from going out the door, and it’ll show you exactly where every A4358 submission stands.

Book a demo to see how it fits DME billing into the rest of your practice’s workflow.

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