NPIAP Pressure Injury Staging Guide

Stage 1: Non-Blanchable Erythema

Stage 1 is the earliest detectable sign of injury. It is characterized by non-blanchable erythema of intact skin. "Non-blanchable" means that when you apply pressure to the reddened area, it does not turn white (blanch); it remains red.

At this stage, the skin is still intact, but the underlying blood vessels are reacting to pressure. You may notice changes in the area's temperature (feeling warmer or cooler than surrounding skin) or firmness.

Stage 2: Partial-Thickness Skin Loss

Stage 2 involves partial-thickness skin loss where the damage extends into the dermis. The wound bed typically appears pink, red, or moist.

A key diagnostic feature of Stage 2 is that it may present as an intact or ruptured serum-filled blister. It is vital to note that in Stage 2, adipose (fat) tissue is not visible, and you will not see granulation tissue or eschar.

Stage 3: Full-Thickness Skin Loss

Stage 3 represents full-thickness skin loss. At this level, the damage has penetrated through the epidermis and dermis, making adipose (fat) tissue visible in the wound bed.

Several clinical features may be present in Stage 3:

• Granulation tissue: New connective tissue and tiny blood vessels that form during the healing process.
• Epibole: The edges of the wound may become rolled.
• Slough or Eschar: You may see yellowish/tan/gray necrotic tissue (slough) or dark, leathery necrotic tissue (eschar).
• Undermining and Tunneling: The injury may extend beneath the skin surface (undermining) or create narrow tracts (tunneling).

Crucially, in Stage 3, fascia, muscle, tendon, cartilage, or bone are not exposed.

Stage 4: Full-Thickness Tissue Loss

Stage 4 is the most severe stage of visible tissue destruction. This stage involves the full-thickness loss of skin and all underlying tissues, with exposed or directly palpable fascia, muscle, tendon, cartilage, or bone.

Like Stage 3, Stage 4 may present with slough, eschar, or epibole, but the depth of the wound indicates significant structural damage.

Special Classifications: Unstageable Injuries

Sometimes, a clinician cannot accurately determine the stage of a pressure injury. This is classified as an Unstageable Pressure Injury.

An injury is unstageable when the true extent of tissue loss is obscured by slough or eschar. Because the wound bed is covered by this necrotic material, the clinician cannot see whether the damage only reaches the dermis or extends down to the bone.

Clinical Note: If slough or eschar is present on the heel(s), it should not be debrided or removed until the extent of the injury is properly assessed.

Summary Table of Staging