Your NPWT Claim Dies on Criterion A — Not the Wound (E2402)

Nobody's arguing the wound is real

Negative pressure wound therapy has an odd position in DME coverage. Unlike a CPAP or a power wheelchair, where the fight is usually over whether the patient qualifies at all, NPWT starts from an assumption that the patient already has a serious problem. A chronic Stage III or IV pressure ulcer. A diabetic foot ulcer that isn't closing. A dehisced surgical wound. Nobody at the MAC is questioning whether that wound exists.

What they're questioning is whether NPWT should have started when it did. The LCD treats the pump as a step you take after the standard wound therapy program has been tried, or specifically considered and ruled out. That "tried or ruled out" language is doing all the work in this policy, and it's the part almost nobody documents cleanly, because clinically the decision to move to NPWT often happens fast, in a conversation between a physician and a wound care nurse that never gets written down the way the LCD wants it written down.

"The pump is never the hard part to justify. The hard part is proving, in writing, that everything ordinary was tried before anyone reached for it."

The rules live in LCD L33821 and its companion policy article, and the DME MACs have published their CERT findings on exactly where NPWT claims fail. The pattern is consistent enough that it's worth building your intake process around it directly, rather than treating each denial as its own surprise.

Criterion A: the four things every wound needs, plus the ones specific to yours

Criterion A covers ulcers and wounds treated in the home setting: chronic Stage III or IV pressure ulcers, neuropathic ulcers like diabetic foot ulcers, venous or arterial insufficiency ulcers, or a chronic ulcer of mixed origin that's been present at least 30 days. Before NPWT is reasonable and necessary for any of these, the LCD wants a complete wound therapy program addressed first — and it breaks into two layers.

The first layer applies to every wound type, no exceptions. The chart needs to show a licensed medical professional evaluating and measuring the wound, dressings applied to keep it in a moist environment, debridement of any necrotic tissue, and the patient's nutritional status evaluated and addressed. Four items. All four, not three. Nutritional status is the one that gets skipped most often, because it feels tangential to a wound note — but the LCD treats it as load-bearing.

The second layer depends on the wound. A Stage III or IV pressure ulcer needs documented turning and positioning, use of a group 2 or 3 support surface on the posterior trunk or pelvis, and management of moisture and incontinence. A neuropathic ulcer needs a comprehensive diabetic management program plus documented offloading of pressure on the affected foot. A venous insufficiency ulcer needs consistently applied compression bandages or garments, plus leg elevation and ambulation actively encouraged. Each of these has to show up as something that happened, or something specifically considered and ruled out — not just implied by the diagnosis.

None of this means the ordering physician did anything wrong clinically. In most cases the standard measures genuinely were tried, or genuinely didn't make sense for that patient. The problem is that the decision lived in a conversation, or in a general wound care note that never spelled out each element the LCD is checking for. A reviewer can't credit what isn't written down, and "the wound clearly needed it" isn't a documentation standard Medicare recognizes.

Criterion B: the inpatient path most coordinators never learn

Criterion A isn't the only door into coverage. Criterion B covers wounds encountered in an inpatient setting, and it works two ways. Either the wound described under Criterion A shows up in the hospital and the standard measures have already been tried or ruled out, with NPWT judged by the treating physician to be the best available option — or the patient has a surgically created wound, like a dehiscence, or a traumatic wound such as a pre-operative flap or graft, where the record documents medical necessity for accelerated granulation tissue that other topical treatments can't achieve.

Suppliers who only ever bill NPWT for home-setting chronic ulcers sometimes miss that this second path exists, or bill it without pulling the documentation that supports it. A dehisced surgical wound has a different clinical story than a Stage IV pressure ulcer, and the chart needs to tell that specific story — the complication, why standard topical treatment won't get there fast enough, and why NPWT is the better option in the treating physician's judgment.

Criterion C: coverage doesn't stay approved on autopilot

This is the one that catches suppliers who did everything right at the start. Getting past Criterion A doesn't mean the rental keeps paying itself. For coverage to continue, a licensed medical professional has to directly assess the wound on a regular basis, supervise or directly perform the dressing changes, and — at minimum once a month — document changes in the wound's dimensions and characteristics.

"The first month's paperwork gets all the attention. The fourth month's paperwork is what actually keeps the rental paid."

In practice, this is where a lot of NPWT files quietly go stale. The initial workup is thorough because everyone knows the claim will be scrutinized. Then the wound starts improving, visits get less frequent, and the monthly measurement note becomes a formality that sometimes doesn't happen at all. If a reviewer pulls the file six months in and can't find that monthly wound-dimension documentation, the ongoing rental is exposed even though the original order was clean.

The written order, and the trap hiding in Part A stays

E2402 requires a written order prior to delivery — the prescription has to exist before the pump goes out, not get backfilled after the fact. That's a separate failure point from Criterion A, and CERT reviews still catch it: a missing detailed written order accounted for roughly one in eleven of the reasonable-and-necessary-adjacent denials in the same review that surfaced the Criterion A numbers above.

There's one more trap that's easy to miss because it has nothing to do with the wound at all. DME is only separately payable when it's provided for use in the patient's home. If the date of service falls inside a covered Part A stay, the equipment isn't separately reimbursable by the DME MAC — it's bundled into the facility payment. A discharge date that shifts by a day, or a pump that goes out before the patient is actually home, is enough to trigger this denial regardless of how solid the wound documentation is.

What your intake team should confirm before an NPWT pump ships

This isn't the entirety of L33821 — it's the practical triage that catches the failures above, run before the order enters the queue rather than after a denial or a CERT letter arrives.

The problem is the moment, not the wound care team

Every failure point above shares the same shape. The clinical decision was almost certainly correct. The wound care nurse and the physician knew what they were treating and knew why NPWT made sense. What's missing isn't judgment — it's the specific, LCD-shaped paper trail that turns that judgment into a claim a reviewer can approve without a fight.

Reconstructing that paper trail after a denial means going back to a physician's schedule from weeks ago and asking them to remember, and document, decisions they made quickly and correctly at the bedside. That's slow, and it isn't always possible. Catching the same gap before the order ships costs a phone call or a chart note, made while the visit is still fresh.

What to do this week

1. Pull your last quarter of NPWT denials and sort by criterion

Separate the ones that failed Criterion A from the ones that failed on the written order, Criterion B, Criterion C, or the Part A overlap. That split tells you whether the gap is in how the initial order is documented or in how the rental is maintained month over month — and the fixes for those are different.

2. Build a standing template for the base four plus wound-type elements

If your wound care documentation currently lives in free-text visit notes, a structured template that prompts for measurement, dressing, debridement, nutrition, and the wound-specific items closes most of the Criterion A gap on its own.

3. Set a monthly tickler for Criterion C reassessment

Ongoing NPWT rentals need monthly wound-dimension documentation for the life of the rental. A simple recurring check — is this month's measurement note actually in the file — catches the taper-off pattern before six months of billing sits exposed.

The wound qualifies. The pump is the right call. The only real question is whether the file that leaves your intake desk can survive a records request — before the order ships, not after the denial lands.