Ankle Brachial Pressure Index Calculator

Ankle Brachial Pressure Index (ABPI) Calculator

The ABPI is a tool used to screen for Peripheral Artery Disease (PAD). It compares the blood pressure measured at your ankle with the blood pressure measured at your arm.

Arm Systolic Pressure (mmHg)

Ankle Systolic Pressure (mmHg)

Your Results

Right Leg ABPI

Left Leg ABPI

*Results are for informational purposes only. Consult a medical professional for diagnosis.

function calculateABPI() { var rArm = parseFloat(document.getElementById('rightArm').value); var lArm = parseFloat(document.getElementById('leftArm').value); var rAnkle = parseFloat(document.getElementById('rightAnkle').value); var lAnkle = parseFloat(document.getElementById('leftAnkle').value); if (isNaN(rArm) || isNaN(lArm) || isNaN(rAnkle) || isNaN(lAnkle) || rArm <= 0 || lArm <= 0 || rAnkle <= 0 || lAnkle 1.4) return { text: "Calcification / Non-compressible", color: "#e67e22", bg: "#fef5e7" }; if (val >= 1.0 && val = 0.91 && val = 0.7 && val = 0.4 && val <= 0.69) return { text: "Moderate PAD", color: "#d35400", bg: "#fdf2e9" }; return { text: "Severe PAD", color: "#c0392b", bg: "#f9ebeb" }; } var rStatus = getStatus(parseFloat(rightABPI)); var lStatus = getStatus(parseFloat(leftABPI)); document.getElementById('rightVal').innerText = rightABPI; document.getElementById('rightStatus').innerText = rStatus.text; document.getElementById('rightStatus').style.color = rStatus.color; document.getElementById('rightResultBox').style.backgroundColor = rStatus.bg; document.getElementById('leftVal').innerText = leftABPI; document.getElementById('leftStatus').innerText = lStatus.text; document.getElementById('leftStatus').style.color = lStatus.color; document.getElementById('leftResultBox').style.backgroundColor = lStatus.bg; document.getElementById('abpiResult').style.display = 'block'; }

Understanding the Ankle Brachial Pressure Index (ABPI)

The Ankle Brachial Pressure Index (ABPI) is a simple, non-invasive clinical test used to assess the vascular health of the lower limbs. By comparing the systolic blood pressure at the ankle with the highest systolic pressure measured in the arms, clinicians can detect the presence of Peripheral Artery Disease (PAD).

How is ABPI Calculated?

The formula for ABPI is straightforward: divide the highest systolic blood pressure measured at the ankle by the highest systolic blood pressure measured in the arms. In a healthy individual, the pressure in the legs should be equal to or slightly higher than the pressure in the arms.

ABPI = Highest Ankle Systolic Pressure / Highest Arm Systolic Pressure

Interpreting Your Results

The resulting ratio helps identify the degree of arterial obstruction. Use the following standard medical guidelines to understand the results:

ABPI Range	Interpretation
> 1.40	Non-compressible arteries (often due to calcification in patients with diabetes)
1.00 – 1.40	Normal (Healthy blood flow)
0.91 – 0.99	Borderline PAD
0.70 – 0.90	Mild Peripheral Artery Disease
0.40 – 0.69	Moderate Peripheral Artery Disease
< 0.40	Severe Peripheral Artery Disease (Risk of critical limb ischemia)

Practical Example

Imagine a patient with the following systolic readings:

• Right Arm: 130 mmHg | Left Arm: 125 mmHg (Highest Arm = 130)
• Right Ankle: 110 mmHg
• Left Ankle: 140 mmHg

Right ABPI: 110 / 130 = 0.85 (Mild PAD)

Left ABPI: 140 / 130 = 1.08 (Normal)

Why is the ABPI Important?

PAD is a condition where plaque builds up in the arteries that carry blood to your legs. Left untreated, it can lead to pain while walking (claudication), non-healing wounds, and in severe cases, gangrene or amputation. Furthermore, a low ABPI is often an indicator of systemic atherosclerosis, meaning the patient may be at a higher risk for heart attack or stroke.

Disclaimer: This calculator is a screening tool and does not replace professional medical advice. If you experience leg pain, coldness in the feet, or have sores that won't heal, seek immediate medical attention.