Table 1.

Stages of Pressure Ulcers

Stage	Descriptions
Suspected Deep Tissue Injury	Purple or maroon localized area of discolored intact skin or blood-filled blister due to damage underlying soft tissue from pressure and/or shear force. The area may be preceded by tissue that is firm, mushy, boggy, warmer or cooler, when compared to adjacent tissue.
Stage 1	Intact skin with non-blanchable redness of localized area, usually over a bony prominence. Darkly pigmented skin may not have visible blanching; its color may differ from the surrounding area.
Stage 2	Partial Thickness loss of dermis presenting as a shallow open ulcer with a red/pink wound bed, without slough, May also present as an intact or open/ruptured serum-filled blister.
Stage 3	Full thickness tissue loss. Subcutaneous fat may be visible, but bone, tendon or muscles are not exposed. Slough may be present, but does not obscure the depth of tissue loss. May include undermining and tunneling.
Stage 4	Full thickness tissue loss with exposed bone, tendon or muscle. Slough or eschar may be present in some parts of the wound bed. Often includes undermining and tunneling.
Unstageable	Full thickness tissue loss in which the base of ulcer is covered by slough (yellow, tan, gray, green or brown) and/or eschar (tan, brown or black) in the wound bed.

National Pressure Ulcer Advisory Panel (NPUAP)⁸