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

Every month that passes, some of a facility's Medicare Part B claims expire. Not because they were denied, and not because they were reviewed and rejected. Because no one filed them.

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 does not come back. For any supply furnished to a Part B-eligible resident in the past year that was never billed, the window may still be open.

What the 12-Month Window Actually Means

42 CFR 424.44(a) sets the rule: a Part B claim must be filed within one calendar year of the date of service. For a supply furnished on September 1, 2025, the last possible filing date is September 1, 2026. After that, the claim is non-payable.

CMS allows extensions in four narrow situations: administrative error by an employee, Medicare contractor, or agent of the government; retroactive Medicare entitlement; 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.

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. Consolidated billing, established by the Balanced Budget Act of 1997, means the SNF per diem covers most services during a covered Part A stay. Outside a covered stay, only therapy remains bundled and Part B billing authority opens up across the supply categories.

Three resident groups account for most of what a SNF revenue recovery review finds:

• Residents in non-covered Part A days who were receiving supplies throughout
• Residents who transitioned 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

The Five Supply Categories in the Lookback

The categories eligible for Part B billing under a SNF's own NPI are surgical dressings, ostomy supplies, urological supplies, tracheostomy supplies, and splints and orthotics.

• Surgical dressings. Wound care supplies ordered by a physician with a valid Standard Written Order. In our experience this is the highest-volume missed category: dressing changes are charted in the MAR daily and claims go unfiled monthly.
• Ostomy supplies. Pouches, skin barriers, and accessories are recurring and predictable. The question is whether they are being billed.
• Urological supplies. Catheters, drainage bags, and irrigation supplies are high-frequency and well documented.
• Tracheostomy supplies. Lower prevalence in most buildings, but every resident with a trach generates billable supply needs weekly.
• Splints and orthotics. Custom-fabricated and off-the-shelf, with a physician order and functional documentation in the chart.

Two scope notes. Burst bills enteral nutrition for Medicare Advantage residents only; under traditional Medicare, enteral nutrition runs through the DME MAC pathway rather than the facility's A/B MAC claim. Burst does not bill durable medical equipment, which falls under a separate regulatory framework.

What the Lookback Actually Involves

A 12-month Part B lookback is an A/R 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. Where the record shows supplies dispensed and the billing system shows no Part B claim, you have a potentially billable item.

To file, four things need to be in place: a valid Standard Written Order in the chart at the time of service, documentation of medical necessity, proof of delivery (typically the MAR or nurse documentation), and the claim submitted under the facility's own NPI within 12 months of the date of service.

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 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, category by category. The systems do not always connect and the workflows do not overlap.

The clinical record in PointClickCare or a similar EHR shows the supply was dispensed. The billing system shows no claim. Connecting those two facts is what the lookback does. Burst's PointClickCare Marketplace integration provides read-only access to clinical records so that cross-reference runs without staff pulling charts manually, and the work is contingency only: no recovery, no fee.