Vascular
Nerve health
Skin
Foot X-ray
Metabolic and comorbidities
Comorbidities
Demographics and access
Result and care pathway
Care pathway
Actions triggered by specific findings
Research record
Scoring reference
Vascular points
| Finding | Points | Basis |
|---|---|---|
| ABI 1.00–1.40 | 0 | Normal (ACC/AHA 2024) |
| ABI 0.91–0.99 | 2 | Borderline |
| ABI 0.80–0.90 | 3 | PAD; WIfI ischemia 0 |
| ABI 0.60–0.79 or toe pressure 40–59 mmHg | 5 | WIfI ischemia 1 |
| ABI 0.40–0.59 or toe pressure 30–39 mmHg | 8 | WIfI ischemia 2 |
| ABI <0.40 or toe pressure <30 mmHg | 10 + red flag | WIfI ischemia 3; IWGDF urgent imaging threshold |
| TBI <0.70 (any toe pressure ≥60) | 3 | Abnormal TBI (ACC/AHA 2024) |
| ABI >1.40 without TBI or toe pressure | 4, provisional | Noncompressible; cannot exclude PAD |
When several measures are entered, the worst one sets the score.
ENFD reference ranges (MED AI DX SOP)
Lower limit of normal (LLN) is the 5th percentile. Mild: 66–99% of LLN. Moderate: 33–66%. Severe: below 33%. The tool uses the exact fiber/mm boundaries from the SOP tables. Ages under 20 use the 20–29 row.
| Age | Distal leg F | Distal leg M | Ankle F | Ankle M |
|---|---|---|---|---|
| 20–29 | 7.2 | 5.7 | 6.7 | 5.4 |
| 30–39 | 6.5 | 4.9 | 6.1 | 4.7 |
| 40–49 | 5.7 | 4.2 | 5.2 | 4.0 |
| 50–59 | 4.9 | 3.4 | 4.1 | 3.2 |
| 60–69 | 4.2 | 2.6 | 3.3 | 2.4 |
| 70+ | 3.4 | 1.8 | 2.7 | 2.0 |
| Site (all ages, both sexes) | LLN | Mild | Moderate | Severe |
|---|---|---|---|---|
| Proximal thigh | 13.6 | 9.1–13.5 | 4.6–9.0 | <4.6 |
| Distal foot / toes | 7.2 | 4.0–7.1 | 1.5–3.9 | <1.5 |
| Distal forearm | 6.7 | 4.8–6.6 | 2.3–4.7 | <2.3 |
| Fingers | 6.5 | 4.4–6.4 | 2.3–4.3 | <2.3 |
| Nerve pillar component | Points |
|---|---|
| Worst distal lower-limb site (distal leg, ankle, foot): WNL / mild / moderate / severe | 0 / 1 / 2 / 3 |
| Upper-limb site also reduced while a distal leg site is reduced (stocking-glove spread) | +1 |
| LOPS on 10 g monofilament | +5 |
| Reduced or absent vibration | +1 |
Length dependency compares each site to its own normal range (thigh density is normally 3–4 times distal leg density), then compares the worst distal lower-limb site with the thigh as percentages of their lower limits. Distal reduced with a normal thigh is length-dependent, the expected diabetic pattern. When both are reduced, a distal percentage at or below 80% of the thigh percentage is length-dependent with proximal spread; any smaller distal-predominant gradient (distal percentage below the thigh percentage, or a worse distal grade) is reported as suggestive of length dependency; thigh percentage equal to or up to 20% below distal is diffuse; thigh reduced more than distal, or a reduced thigh with a spared distal leg, is non-length-dependent and prompts a search for other causes. The 20% band is this tool’s convention. Symmetry compares left and right at the same site: a normal-versus-reduced mismatch, or a gap of two or more severity grades, is flagged. The foot score always uses the worse side. The symmetry threshold is this tool’s convention, not a published standard.
Composite bands and IWGDF categories
| Tier | Composite | IWGDF 2023 criteria | Screening interval |
|---|---|---|---|
| 0 Very low | 0–9 | No LOPS and no PAD | Every 12 months |
| 1 Low | 10–29 | LOPS or PAD | Every 6–12 months |
| 2 Moderate | 30–49 | LOPS + PAD, LOPS + deformity, or PAD + deformity | Every 3–6 months |
| 3 High | 50–100 | LOPS or PAD plus history of ulcer, amputation, or ESRD | Every 1–3 months |
| Urgent | Any | Active ulcer, active Charcot, suspected osteomyelitis, or critical ischemia | Immediate referral |
Composite = 2.5 × vascular + 2.5 × nerve + 2 × skin + 1.5 × X-ray + 1.5 × metabolic, each pillar scored 0–10, rounded. Weights favor PAD and LOPS because IWGDF identifies them as the primary drivers of ulceration.
Metabolic lab points
| Marker | Points | Basis |
|---|---|---|
| HbA1c <5.7 / 5.7–6.9 / 7.0–7.9 / 8.0–8.9 / 9.0–9.9 / ≥10% | 0 / 1 / 2 / 3 / 4 / 5 | ADA: prediabetes 5.7–6.4, diabetes ≥6.5, general target <7; UKPDS 35 and EURODIAB link each rise to microvascular and neuropathy risk |
| eGFR ≥60 / 45–59 / 30–44 / 15–29 / <15 or dialysis | 0 / 1 / 2 / 3 / 4 | KDIGO 2024 G1–2, G3a, G3b, G4, G5 |
| UACR <30 / 30–299 / ≥300 mg/g | 0 / 1 / 2 | KDIGO A1, A2, A3 |
| B12 ≥300 / 200–299 / <200 pg/mL | 0 / 1 / 2 | Borderline range warrants methylmalonic acid; reversible neuropathy cause (ADA; DPPOS) |
| Diabetes duration ≥10 years | 1 | EURODIAB neuropathy risk factor |
| Current tobacco use | 1 | EURODIAB; PAD and amputation risk |
| Diabetic retinopathy | 2 | Independent DFU predictor (Seattle Diabetic Foot Study) |
| Hypertension; coronary disease; stroke; heart failure; autonomic neuropathy; heavy alcohol use | 1 each | EURODIAB risk factors; systemic atherosclerosis; healing and self-care limits |
| Race, ethnicity, barriers to care | 0 | Recorded and used to lower the threshold for objective testing and shorten follow-up, not to move the score (see methodology) |
Capped at 10. Lipids, triglycerides, albumin and BMI were removed on purpose: each moved the score by one point and rarely changed the foot visit; LDL management is folded into the PAD action. IWGDF does not use labs to set risk category, so this pillar can raise the composite band but never lowers the IWGDF floor. Dialysis or eGFR <15 also counts as end-stage renal disease for the IWGDF category.
Methodology and limits
Every cut-point comes from a published guideline or reference study (listed below). ENFD grading follows the MED AI DX reference range SOP. The point weights, the composite bands, and the symmetry threshold are a proposed framework and have not been validated as a single instrument. The thigh LLN is not age-adjusted, so interpret an isolated mild thigh reduction in older patients with caution before calling a pattern non-length-dependent. To keep the tool safe, the final tier can never fall below the IWGDF 2023 category, and red-flag findings always route to the urgent pathway. The composite adds granularity above IWGDF (for example, severe combined small- and large-fiber loss can move a patient up a tier) and captures early small-fiber neuropathy that monofilament testing misses. Before citing it as validated, test it against 12- and 24-month ulcer and amputation outcomes in your own cohort (discrimination and calibration). Race and ethnicity are recorded but deliberately not scored. US data show roughly double the amputation rate and lower PAD detection in Black, Hispanic and American Indian patients, but the drivers are access, detection and treatment rather than biology, so the tool responds by recommending more objective testing and closer follow-up instead of adding points. This mirrors the removal of race from eGFR equations (NKF-ASN 2021) and the HHS Section 1557 rule (45 CFR 92.210) requiring reasonable efforts to prevent discrimination from race-based clinical algorithms; recording race lets the registry measure outcomes by group. Prediabetes is supported: dysglycemia scores from an HbA1c of 5.7, but the IWGDF intervals were validated in diabetes. Metabolic labs and comorbidities extend the model beyond IWGDF: a patient with poor control but no LOPS or PAD can move from Tier 0 to Tier 1. This tool supports, and does not replace, clinical judgment.
References
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- Fitridge R, Chuter V, Mills J, et al. The intersocietal IWGDF, ESVS, SVS guidelines on peripheral artery disease in people with diabetes and a foot ulcer. Diabetes Metab Res Rev. 2024;40(3):e3686.
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- Eichenholtz SN. Charcot Joints. Springfield, IL: Charles C Thomas; 1966.
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- US Department of Health and Human Services. Nondiscrimination in health programs and activities, 45 CFR §92.210 (use of patient care decision support tools). 2024.
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