What is the Ankle-Brachial Index (ABI)?

ABI is the ratio of blood pressure at the ankle to blood pressure in the arm. It's a non-invasive screening test for peripheral artery disease (PAD).

How do I interpret ABI results?

Normal: 1.0-1.4. Borderline: 0.91-0.99. Mild PAD: 0.71-0.90. Moderate PAD: 0.41-0.70. Severe PAD: ≤0.40. ABI >1.4 suggests calcified arteries.

Who should be screened with ABI?

Adults over 65, ages 50-64 with risk factors (smoking, diabetes), anyone with leg symptoms (claudication), and all diabetics regardless of age.

What does ABI > 1.4 mean?

ABI >1.4 indicates non-compressible (calcified) arteries, common in diabetes and chronic kidney disease. Toe-brachial index may be more accurate in these patients.

What are symptoms of PAD?

Claudication (leg pain with walking that improves with rest), leg numbness/weakness, cold legs/feet, non-healing wounds, and skin color changes.

Using a blood pressure cuff and Doppler probe, measure systolic pressure at both ankles (dorsalis pedis and posterior tibial) and both arms, then calculate the ratio.

ABI Calculator

Calculate Ankle-Brachial Index to screen for Peripheral Arterial Disease (PAD)

Enter Blood Pressure Readings

1Brachial (Arm) Systolic Pressures

Right Arm (mmHg)

Left Arm (mmHg)

2Ankle Pressures - Dorsalis Pedis (DP)

Right Ankle DP (mmHg)

Left Ankle DP (mmHg)

3Posterior Tibial (PT) - Optional

Right PT (mmHg)

Left PT (mmHg)

Higher of DP or PT will be used for each leg

Formula

ABI = Ankle Systolic Pressure ÷ Higher Arm Systolic Pressure

ABI Interpretation Guide

> 1.40

Non-compressible- Calcified arteries

1.00 - 1.40

Normal- No significant PAD

0.91 - 0.99

Borderline- Mild disease possible

0.41 - 0.90

Moderate PAD- Claudication likely

≤ 0.40

Severe PAD- Critical limb ischemia

Clinical Tool

For healthcare professionals. ABI is a screening tool and should be interpreted with clinical context. Further diagnostic testing may be required.

About ABI Calculator - Ankle Brachial Index

Calculate Ankle-Brachial Index for peripheral artery disease screening. Essential vascular assessment tool.

Our **ABI Calculator** computes the Ankle-Brachial Index to screen for peripheral artery disease (PAD). ABI is a simple, non-invasive test comparing blood pressure at the ankle to the arm. It's a key screening tool for vascular health. For cardiac risk, see our BMI Calculator.

A normal ABI is 1.0-1.4. Values below 0.9 indicate PAD, with lower values suggesting more severe disease. Values above 1.4 may indicate non-compressible arteries (calcification), common in diabetes. Our calculator provides interpretation and recommendations.

PAD affects millions worldwide and is associated with increased cardiovascular events. Early detection through ABI screening allows for risk factor modification and treatment. Use our Water Intake Calculator for overall health optimization.

Key Features

ABI calculation for both legs

PAD severity classification

Symptom checklist

Risk factor assessment

Follow-up recommendations

Visual result display

Why Use This Tool?

Non-invasive PAD screening

Early disease detection

Risk stratification

Guide treatment decisions

Monitor disease progression

Common Use Cases

Primary Care Screening: Screen at-risk patients for PAD.

Diabetes Management: Monitor vascular complications.

Cardiology: Assess overall cardiovascular risk.

Vascular Surgery: Baseline and follow-up assessment.

Technical Information

ABI = highest ankle pressure / highest arm pressure
Normal: 1.0-1.4
Borderline: 0.91-0.99
Mild PAD: 0.71-0.90
Moderate PAD: 0.41-0.70
Severe PAD: ≤0.40

How to Use

Measure ankle systolic pressure (both legs)

Measure brachial systolic pressure (both arms)

Enter measurements

View ABI values and interpretation