A Look at the UT and Wagner Scale Diabetic Foot Ulcer Classification Systems

Published on August 19, 2021 by Carole Jakucs, MSN, RN, PHN, CDCES

Given the fact that DFUs occur in approximately 15% of patients with diabetes and there are more than 34 million people in the U.S. with diabetes, using a relevant diabetic foot ulcer classification system for patients is essential.

There are several diabetic wound classification systems. But how do you choose which one to use?

This decision generally involves clinician preference along with the organization’s policy.

Two wound care specialists provide an overview of two systems for DFU classification: The Wagner Scale and the University of Texas (UT) Diabetic Wound Classification System.

“I use the Wagner Scale in my office,” said Pam Sabet, DPM, a podiatrist who specializes in wound care in the Department of Wound Care and Hyperbaric Medicine at UC San Diego Health in San Diego. “It’s widely accepted, simple to use, and easy to understand across the board.”

One drawback to the Wagner Scale is that it doesn’t describe infected or ischemic wounds, said Sabet, who also is an associate clinical professor at the University of California San Diego School of Medicine’s Department of Orthopedic Surgery. “However, I document extensively in my clinical notes to describe infected and/or ischemic wounds.”

Mariam Botros, DPM, AACFAS, a podiatrist in the Podiatry, Wound Healing, and Hyperbaric Oxygen Center with MemorialCare at Long Beach Medical Center in Long Beach, California, uses the UT System in her daily practice.

Botros studied podiatry at the Western University of Health Sciences in Pomona, California, under Lawrence B. Harkless, DPM, one of the creators of the UT Diabetic Wound Classification System. She learned the UT system in podiatry school.

One purpose of using a specific system to accurately diagnose and stage DFUs is to guide medical treatment. “It’s important for clinicians to back up their thought process regarding what they found during the physical exam and determine the progression or regression of a wound or wounds,” said Botros.

Another function for accurate diagnosis of DFUs is to determine if other disciplines are needed for the patient. “Your diagnosis may result in one or more referrals to another specialist of the healthcare team,” she said. “One example? Sending a patient for further evaluation for a vascular consult and possible vascular studies.”

Accurate staging is also needed for insurance purposes, said Sabet.

Overview of the Wagner Ulcer Grade Classification System

Sabet pointed out the Wagner Scale assesses ulcer depth and the presence of osteomyelitis or gangrene by using the following grades:

  • Wagner Grade 0: No open lesion or a preulcerative lesion — may have a deformity or
  • cellulitis
  • Wagner Grade 1: Partial- or full-thickness ulcer (superficial)
  • Wagner Grade 2: Deep ulcer extended to ligament, tendon, joint capsule, bone, or deep fascia without abscess or osteomyelitis (OM)
  • Wagner Grade 3: Deep abscess, OM, or joint sepsis
  • Wagner Grade 4: Partial-foot gangrene
  • Wagner Grade 5: Whole-foot gangrene

Overview of the UT Grading System

The grades of the UT system include:

  • Grade 0: Pre- or postulcerative site (epithelialized wound)
  • Grade 1: Superficial wound, not involving tendon, capsule, or bone
  • Grade 2: Wound is penetrating to tendon or capsule
  • Grade 3: Wound is penetrating bone or joint

Within each wound grade there are four stages:

  • Stage A: Clean wounds (no infection, no ischemia)
  • Stage B: Nonischemic, infected wounds
  • Stage C: Ischemic, noninfected wounds
  • Stage D: Ischemic and infected wounds (both present)

According to Sabet, the University of Texas (UT) system is more descriptive. “It assesses ulcer depth, combines grade and stage, assesses the presence of wound infection and clinical signs of lower-extremity ischemia, and shows a greater association with increased risk of amputation and prediction of ulcer healing when compared with the Wagner system, based on several studies,” she said.

Additionally, the UT system uses a matrix of grade on the horizontal axis and stage on the vertical axis, Sabet said.

How Assessment of DFUs Determines Treatment

Various factors for each wound contribute to clinical decision making when it comes to the selection of specific treatments, according to Sabet.

The wound characteristics you’ll want to consider can include (but are not limited) to:

  1. Wound size
  2. Wound depth
  3. Wound base appearance
  4. Presence of sinus tracts
  5. Probe to bone
  6. Amount of granular versus fibrotic or dysvascular tissue
  7. Drainage
  8. Signs of infection
  9. Evaluation of exposed structures such as tendon and bone
  10. Vascular component

Sabet emphasized it’s imperative to evaluate for vascular and arterial disease. “This is an important component to treating diabetic foot ulcers.”

It’s also essential to check for signs of infection, which can include clinical indicators such as erythema, edema, pain, tenderness, and warmth, she said.

When clinical infection is suspected, cultures taken from the wound can be useful in determining the appropriate antibiotic therapy. “Although the most frequent infections are due to aerobic Gram-positive cocci and aerobic Gram-negative organisms, anaerobic organisms are often isolated.”

Clinically uninfected ulcers should not be cultured, as the recovered organisms will contain only colonizing flora. “Empirical antibiotic therapy should be started and revised, if necessary, once culture results are obtained.”

Wounds that are staged as a Wagner grade 3 or higher, that have failed conventional wound care for 30 days, can be referred for hyperbaric medicine consultation, she said.

If there is a bone infection, IV antibiotics, surgical debridement, or amputation might be necessary.

Regarding patient outcomes in relation to the stage of their DFU, Botros stated the higher the stage, the higher the risk of bone involvement.

“The higher the stage, combined with the presence of infection and/or ischemia, the higher the risk of amputation,” Sabet added.


Become a Diabetic Wound professional and help save the lives and limbs of patients. Take the first step by registering for one of our Diabetic Wound Management Courses.


Carole Jakucs, MSN, RN, PHN, CDCES

Carole Jakucs, MSN, RN, PHN, CDCES, is a freelance writer and diabetes educator. Her background in nursing includes tenures in healthcare management and as a care provider. She has worked in med/surg/telemetry, a pediatric emergency department and college health.