A pressure injury staging error on the medical record carries direct billing consequences. An admission note that understates a Stage 3 wound as a Stage 2, or that omits a clear present on admission (POA) determination, becomes the document an auditor relies on months later. Under the Centers for Medicare & Medicaid Services (CMS) hospital-acquired condition (HAC) payment provision, a Stage 3, Stage 4, or unstageable pressure injury coded as not present on admission can strip the associated diagnosis from the facility's MS-DRG payment calculation entirely, and can support a later overpayment demand or a False Claims Act theory built around the discrepancy between the clinical chart and the billed code.
The Current Staging Framework
The National Pressure Injury Advisory Panel (NPIAP) staging system, the clinical reference CMS coding guidance points to, classifies pressure injuries by tissue depth: Stage 1 (intact skin with localized, non-blanchable erythema), Stage 2 (partial-thickness loss of the epidermis and dermis, presenting as a shallow open wound or an intact or ruptured blister), Stage 3 (full-thickness tissue loss with visible fat but no exposed muscle, tendon, or bone), and Stage 4 (full-thickness loss with exposed or directly palpable muscle, tendon, ligament, or bone). Two additional categories describe wounds that cannot yet be assigned a numeric stage: Unstageable (full-thickness loss obscured by slough or eschar, until debridement reveals the true depth) and Deep Tissue Pressure Injury (persistent non-blanchable deep red, maroon, or purple discoloration indicating damage below intact or non-intact skin). Current guidance uses "pressure injury" rather than the older "pressure ulcer" label, because several of these stages involve no open wound at all, a distinction auditors increasingly expect clinical documentation to track precisely.
Present on Admission and the HAC Payment Rule
Every diagnosis on an inpatient claim carries a POA indicator: "Y" (present on admission), "N" (not present on admission, i.e., hospital-acquired), "U" (documentation insufficient to determine), or "W" (clinically undeterminable). Stage 3, Stage 4, and unstageable pressure injuries sit on CMS's HAC list. Under the rule in effect since October 1, 2008, when one of these conditions is coded "N," "U," or "W," the diagnosis is excluded from the case's severity calculation and the hospital receives no additional payment attributable to it, even though the underlying care was rendered. Coding guidance also treats a wound that progresses in stage during the admission, for example a Stage 2 present on admission that advances to Stage 3 before discharge, as POA for the higher stage, because the injury itself, not merely its final depth, originated before the encounter. Getting that distinction wrong creates exposure in both directions: an inflated POA rate misrepresents the facility's actual acquisition record, and an understated one forfeits payment the facility earned.
A single missed or misapplied stage on the admission wound assessment can reclassify a pressure injury as hospital-acquired rather than present on admission, with direct consequences for MS-DRG payment and for the facility's public HAC measures.
Where Billing Exposure Actually Originates
In practice, the exposure rarely comes from a single dramatic charting error. It accumulates from an admission wound assessment completed hours after the patient arrives, a staging note that does not specify tissue depth with the precision the NPIAP framework requires, or a wound that is documented as unstageable on admission but never re-staged after debridement. Reviewers working under a Local Coverage Determination (LCD) or a Unified Program Integrity Contractor (UPIC) audit routinely compare the admission note, the nursing flow sheets, and the final ICD-10-CM code for internal consistency. A stage recorded on the coding summary that is not supported by a contemporaneous clinical note, or a POA indicator that contradicts the admission assessment, is precisely the kind of discrepancy that turns a routine review into a broader UPIC wound care audit, with recoupment demands reaching back across the claims history.
Why Early Legal Counsel Is Critical
It is critical that healthcare providers promptly retain experienced healthcare defense counsel upon receiving a subpoena, audit notice, investigative request, or other government inquiry involving pressure injury staging or POA coding. Early legal intervention can protect the provider's rights, ensure appropriate responses to government requests, avoid inadvertent admissions, preserve relevant defenses, and allow counsel to communicate with investigators on the provider's behalf. Delaying legal representation can significantly affect the outcome of a matter and expose the provider to unnecessary risk.
How Health Law Alliance Can Help
Health Law Alliance represents hospitals, skilled nursing facilities, and wound care providers facing staging-related payment reviews, HAC reporting disputes, and False Claims Act exposure tied to POA coding. If a facility has received an audit notice, a recoupment demand, or a request tied to pressure injury documentation, contact us for a free, confidential consultation to review the matter.
