12-Month Medicare Part B Lookback for SNFs: What Can Still Be Billed?

Some Medicare Part B claims are lost for a procedural reason rather than a clinical one. Not because they were denied, and not because they were reviewed and rejected, but because no one filed them inside the window.

Under 42 CFR 424.44, Medicare Part B claims must be submitted within 12 months of the date of service. Once that window closes, the A/B MAC will not process the claim and the revenue is not recoverable.

For any supply furnished to a Part B-eligible resident in the past year that was never billed, the window may still be open. This post walks through what qualifies, what the regulation says, and how to run a practical lookback. It is general information about Medicare billing rules, not billing, legal, or clinical advice for a specific facility.

What the 12-Month Window Actually Means

The timely filing requirement for Medicare Part B is a federal deadline rather than a grace period. 42 CFR 424.44(a) requires a Part B claim to be filed within 1 calendar year of the date of service. For a supply furnished on September 1, 2025, the last filing date is September 1, 2026. After that, the claim is not payable.

CMS allows filing extensions in four narrow situations: administrative error caused by an employee, Medicare contractor, or agent of the government; retroactive Medicare entitlement determinations; retroactive Medicare entitlement involving a state Medicaid agency recoupment; and retroactive disenrollment from a Medicare Advantage plan or PACE organization.

Not knowing to bill an item is not one of them. Neither is an oversight, and neither is a supplier saying it would handle the claim.

Practically, any eligible supply your facility furnished to a Medicare Part B-eligible resident in the last 12 months is potentially recoverable, subject to documentation and coverage requirements.

Who Qualifies: The Resident Status Question

Billing authority for SNF Part B supply claims flows from the benefit categories in Section 1861(s) of the Social Security Act, with the facility billing mechanics set out in CMS Pub. 100-04, Chapter 7. Together they establish when supplies become separately billable under Part B.

Consolidated billing was established by the Balanced Budget Act of 1997. During a covered Part A stay, the SNF per diem covers most services, including these supplies. For residents who are not in a covered Part A stay, only therapy remains bundled, and Part B billing authority opens across the supply categories.

The residents most likely to have missed claims in a lookback window fall into three groups:

• Residents on non-covered Part A days who were receiving supplies throughout
• Residents who moved from a covered Part A stay to Part B-only status, where supply billing did not follow the transition
• Residents who were Part B-only from admission and whose supply orders never generated a Part B claim

In our experience, the Part A to Part B transition is where the most revenue goes uncaptured. A resident exhausts the 100 Medicare Part A days. The supplies continue. The billing stops. That gap is what a lookback surfaces.

The Five Supply Categories in the Lookback

The supply categories eligible for Part B billing under a facility's NPI, per Section 1861(s) of the Social Security Act and CMS Pub. 100-04, Chapter 7, are surgical dressings, ostomy, urological, tracheostomy, and splints and orthotics.

• Surgical dressings. Wound care supplies ordered by a physician with a valid Standard Written Order. Dressing changes are charted in the MAR daily, and in our experience this is where the largest volume of unbilled claims sits.
• Ostomy supplies. Pouches, skin barriers, and accessories. Recurring and predictable, which makes unbilled use easy to spot in the record.
• Urological supplies. Catheters, drainage bags, and irrigation supplies. High-frequency, well-documented items that carry Part B billing authority on non-covered days.
• Tracheostomy supplies. Trach care kits, ties, and cleaning supplies. Lower prevalence, but steady weekly use per resident.
• Splints and orthotics. Custom-fabricated and off-the-shelf. A physician order and functional documentation are required.

What the Lookback Actually Involves

A 12-month Part B lookback is an accounts receivable analysis, not an audit. It cross-references what was furnished against what was billed.

Pull every resident who was on non-covered Part A days or Part B-only status at any point in the last 12 months. Cross-reference against the MAR and supply dispensing records. For each resident, the question is direct: were eligible supplies furnished, and are there corresponding Part B claims in the billing system?

Where the record shows supplies dispensed and no Part B claim submitted, you have a potentially billable item. Filing generally requires four things:

1. A valid Standard Written Order from a physician in the resident's chart at the time of service
2. Documentation of medical necessity
3. Proof of delivery, which for supplies is typically the MAR entry or nurse documentation
4. The claim submitted under the facility's own NPI within 12 months of the date of service

For the facility to receive the payment, the claim has to go out under the facility's own NPI. The compliance backdrop matters here too. CMS's CRUSH initiative, Comprehensive Regulations to Uncover Suspicious Healthcare, launched in February 2026 with DMEPOS suppliers as a primary target, and CMS reports it stopped $1.5 billion in suspected fraudulent DMEPOS billings in 2025.

If a supplier has been billing under its own NPI for your residents during covered Part A stays, when those supplies belonged in the bundled payment, that arrangement is worth a compliance review.

Why Most Facilities Miss This Window

Most SNF billing departments are built around Part A UB-04 claims. Part B supply billing works differently: claim by claim, resident by resident, supply category by supply category. The systems do not always connect and the workflows do not overlap.

The result is predictable. Supplies are furnished, documented, and never billed. Residents move from Part A to Part B and the supply billing does not follow. The window opens, nothing happens, and it closes.

Most facilities use PointClickCare or a similar EHR for clinical documentation. The clinical record shows the supply was dispensed. The billing system shows no claim. Connecting those two facts is what the lookback makes visible.

Burst's PointClickCare Marketplace integration gives us read-only access to clinical records, so the cross-reference runs without your staff pulling charts manually. We work on contingency only: no recovery, no fee.