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Tridien Resource Library

Staging Definitions

Pressure Ulcer

Any lesion caused by unrelieved pressure resulting in damage of underlying tissue. Shear and friction may be contributing factors. Pressure ulcers are usually located over bony prominences and are staged to classify the degree of tissue damage observed.

Stage I

Non-blanchable erythema of intact skin, the heralding lesion of skin ulceration. In individuals with darker skin, discoloration of the skin, warmth, edema, induration, or hardness may also be indicators.

Stage II

Partial thickness skin loss involving epidermis, dermis, or both. The ulcer is superficial and presents as an abrasion, blister, or shallow crater.

Stage III

Full thickness skin loss involving damage to or necrosis of subcutaneous tissue that may extend down to, but not through, underlying fascia. The ulcer presents clinically as a deep crater with or without undermining of adjacent tissue.

Stage IV

Full thickness skin loss with extensive destruction, tissue necrosis, or damage to muscle, bone, or supporting structures (e.g. tendon, joint capsule). Undermining and sinus tracts (tunnels) may also be associated with Stage IV pressure ulcers.

Non-observable: Wound is unable to be visualized due to an orthopedic device, dressing, etc. A pressure ulcer cannot be accurately staged until the deepest viable tissue layer is visible; this means that wounds covered with eschar and/or slough cannot be staged, and should be documented as non-observable.