Since each of the three categories (Wound, Ischemia, and foot Infection) has four grades of severity, the system produces a grid with 64 theoretically possible clinical combinations (WIfI classes).

One of the four limb threat clinical stages was assigned to each of the 64 theoretical patient combinations that would correlate with risk of amputations:

• Clinical stage 1 - Very Low
• Clinical stage 2 - Low
• Clinical stage 3 - Moderate
• Clinical stage 4 - High