Ankle-Brachial Index (ABI)
A simple test comparing blood pressure at the ankle and arm to check for narrowed leg arteries.
Quick Summary
To diagnose peripheral arterial disease.
Ratio of ankle to arm blood pressure.
No preparation; rest for a few minutes first.
Overview
ABI is quick and painless.
Diabetes can make arteries stiff and the result falsely normal.
What It Measures
ABI ratio
Ankle pressure divided by arm pressure.
How It's Performed
- 01
Rest
Lie down for 5–10 minutes.
- 02
Measure
Blood pressure cuffs on arms and ankles with a Doppler probe.
- 03
Calculate
The ratio is worked out.
Reference Ranges
Note: Normal ranges vary by laboratory. Consult your report for the specific reference used.
| Parameter | Typical Range (Adult) | Units |
|---|---|---|
| ABI (normal) | 1.0–1.4 | ratio |
Interpreting Results & Next Steps
Discuss with Doctor
Your doctor will explain the report and what happens next.
If values are Low:
An ABI below 0.9 suggests peripheral arterial disease.
Sources and further reading
Last updated 21 October 2026. For more detail, see these trusted health organisations.
- Peripheral Arterial Disease | PAD(opens in a new tab) · MedlinePlus, US National Library of Medicine