University of Texas Classification of Diabetic Foot Ulcers
The University of Texas (UT) classification system uses a 4×4 matrix combining wound depth grades (0-3) with stages (A-D) based on infection and ischemia status to systematically categorize diabetic foot ulcers and predict complication risk. 1, 2
Structure of the UT Classification System
Depth Grades (0-3)
- Grade 0: Pre- or post-ulcerative lesion that is completely epithelialized 3
- Grade 1: Superficial wound not involving tendon, capsule, or bone 3
- Grade 2: Wound penetrating to tendon or joint capsule 3
- Grade 3: Wound penetrating to bone or deep abscess 1
Stages (A-D) Based on Infection/Ischemia
- Stage A: No infection or ischemia present 3
- Stage B: Infection present, no ischemia 2
- Stage C: Ischemia present, no infection 2
- Stage D: Both infection and ischemia present 2
Clinical Application and Assessment
The UT system requires vascular assessment using clinical signs plus non-invasive testing (transcutaneous oxygen measurements, ankle-brachial index, or toe systolic pressure) to determine ischemia status. 2 This requirement for equipment and clinical expertise reduces feasibility in resource-limited settings compared to simpler classification systems. 2
Prognostic Value
The UT classification successfully predicts complication likelihood, with higher grades and stages correlating with significantly higher amputation rates in wounds deeper than superficial ulcers. 1, 4 Patients with more severe classifications (higher grade/stage combinations) demonstrate worse clinical outcomes. 1
Limitations and Current Recommendations
Key Deficiencies
- Does not include ulcer size/area, which independently predicts outcomes 2
- Does not assess loss of protective sensation (neuropathy), critical for offloading recommendations 2
- Requires vascular testing equipment not universally available 2
- Evidence quality is low with most studies at high risk of bias 2
Important Guideline Caveat
The International Working Group on the Diabetic Foot (2024) strongly recommends AGAINST using the UT system—or any classification system—to predict individual patient outcomes due to weak evidence quality and poor applicability. 2, 4 The positive likelihood ratios are below 5 and negative likelihood ratios around 0.2-0.4, indicating only small changes in pre-to-post test probability of clinical outcomes. 2
Recommended Alternative Approach
For routine clinical communication and documentation, use the SINBAD system instead, which includes site, ischemia, neuropathy, bacterial infection, area, and depth. 4, 3 The SINBAD system has been validated in 12 studies with substantial-to-good reliability. 4
When infection is present or suspected, apply the IDSA/IWGDF infection classification system (grades 1-4) to guide antibiotic selection and hospitalization decisions. 4, 3 This system specifically addresses infection severity from uninfected (grade 1) through mild, moderate, to severe with systemic inflammatory response (grade 4). 1
The UT classification may still be used for research purposes and general communication about wound characteristics, but clinicians should recognize its limitations for individual prognostication and consider supplementing with other assessment tools that capture neuropathy and wound area. 2, 5