Important: This is an educational aid only and does not replace clinical judgement or local policies (e.g., NICE guidelines). Always follow your organisation's protocols for vascular assessment.
ABPI Interpretation Bands
Frequently Asked Questions
The Ankle-Brachial Pressure Index (ABPI) is a simple, non-invasive test used to assess peripheral arterial disease (PAD). It compares the blood pressure measured at the ankle with the blood pressure measured at the arm. A reduced ABPI indicates narrowing or blockage of the arteries in the legs.
Denominator (brachial pressure): The highest systolic pressure from either arm is used.
Numerator (ankle pressure): For each leg, the highest systolic pressure from either the dorsalis pedis (DP) or posterior tibial (PT) artery is used.
The ABPI for each leg is calculated independently: ABPI = (Highest ankle pressure) / (Highest arm pressure)
Consider TBI when:
- ABPI ≥ 1.40 (suggests arterial calcification, making ABPI unreliable)
- Patient has diabetes mellitus or chronic kidney disease (higher risk of arterial calcification)
- Suspected arterial calcification based on clinical assessment
- ABPI results are inconsistent with clinical presentation
TBI is less affected by arterial calcification and provides a more accurate assessment in these cases.
No. This calculator is an educational aid designed to help clinicians and students understand ABPI calculation. It does not replace:
- Clinical assessment and judgement
- Local protocols and NICE guidelines
- Specialist vascular assessment when indicated
- Comprehensive patient evaluation
Always follow your organisation's policies and seek senior advice when uncertain.