Normal Ankle Brachial Index: 5 Essential Numbers Every Patient Must Know

Normal ankle-brachial index (ABI) values fall between 1.00 and 1.40. The ABI is the ratio of the systolic blood pressure at the ankle to the systolic blood pressure in the arm. A value of 1.00 to 1.40 indicates normal lower-extremity arterial blood flow; 0.91 to 0.99 is borderline; 0.41 to 0.90 indicates mild-to-moderate peripheral artery disease (PAD); and 0.40 or lower indicates severe PAD. A value above 1.40 signals noncompressible, calcified arteries and is also considered abnormal. These categories follow the American Heart Association / American College of Cardiology standard for ABI interpretation.

What are normal ankle-brachial index (ABI) values?

A normal ABI is 1.00 to 1.40. The table below shows the standard ABI interpretation categories used by physicians to identify and grade peripheral artery disease.

What ABI value indicates PAD? An ABI of 0.90 or lower confirms peripheral artery disease. An ABI above 1.40 is also abnormal — it reflects calcified, noncompressible arteries rather than healthy circulation, and physicians follow up with a toe-brachial index in that situation. Some older references describe a simplified normal band of 0.90 to 1.30; the AHA/ACC categories above (normal 1.00–1.40, noncompressible above 1.40) are the values most widely used in current clinical reporting.

A normal ankle brachial index (ABI) between 1.00 and 1.40 confirms healthy blood flow from your heart to your legs. This simple, painless test — used to determine a normal ankle brachial index — compares the systolic blood pressure at your ankle to the pressure in your arm, producing a ratio that reveals whether your arteries are open and functioning properly. Physicians across the country use ABI measurement as a frontline diagnostic tool for peripheral artery disease (PAD).

Understanding your normal ankle brachial index transforms a clinical number into actionable insight. Whether you are a patient preparing for testing or a physician evaluating diagnostic technology for your practice, this guide covers exactly what the ABI measures, what the numbers mean, and when additional testing like the Toe Brachial Index (TBI) is needed. In patients with calcified or incompressible vessels, the toe-brachial index provides a reliable alternative when the ABI is unreliable.

What Happens During an ABI Test?

An ABI measurement is completely painless and takes approximately 7 to 10 minutes in a clinical setting. The process feels exactly like getting your routine blood pressure checked, with one important difference: the provider measures systolic pressure in both your arms and your ankles to create a comparison ratio.

To hear blood flow clearly, clinicians use a Doppler ultrasound device, which amplifies the sound of blood moving through your arteries. Modern diagnostic systems like the CMAT Advantage streamline this process by capturing ABI, TBI, and additional cardiovascular markers in a single non-invasive session. The test follows four basic steps:

• Resting period (5-10 minutes): You lie flat so your circulation settles, ensuring accurate baseline readings.
• Cuff placement: Standard blood pressure cuffs wrap around both arms and both ankles.
• Doppler measurement: The provider glides the Doppler wand over your skin to detect pulse sounds while the cuff inflates and deflates.
• Ratio calculation: The highest ankle pressure is divided by the highest arm pressure to produce your ABI score.

Once complete, the provider reviews the measurements to evaluate how blood flow in your legs compares to your arms. Results are available immediately, making the normal ankle brachial index test one of the most efficient vascular tests in clinical practice.

What Is a Normal Ankle Brachial Index Score?

A normal ankle brachial index falls between 1.00 and 1.40. A score of 1.0 means the blood pressure in your ankle exactly equals the pressure in your arm, indicating unobstructed blood flow from your heart to your lower extremities.

Think of this measurement as a percentage of efficiency. A score of 0.95 means your legs receive 95% of the pressure pumped by your heart. Minor variations within the normal range are completely expected and reflect natural differences in individual anatomy.

Medical guidelines from the American Heart Association and the American College of Cardiology establish the following ankle brachial index interpretation scale:

• 1.00 to 1.40: Normal, healthy circulation with no significant arterial narrowing.
• 0.91 to 0.99: Borderline results — acceptable but worth monitoring over time.
• 0.41 to 0.90: Mild to moderate PAD — indicates measurable arterial narrowing that may require further evaluation.
• 0.40 or lower: Severe PAD — indicates critical arterial obstruction requiring prompt medical evaluation.
• Above 1.40: Noncompressible, calcified arteries — the ABI is unreliable and a toe-brachial index is used instead.

These normal ankle brachial index ranges provide physicians with a clear, objective framework for identifying patients who need further vascular evaluation. For practices looking to add ABI and PAD testing capabilities, the CMAT Advantage partnership program includes the diagnostic device, comprehensive training, and ongoing billing support.

What Are the Symptoms of Poor Leg Circulation and PAD?

The hallmark symptom of peripheral artery disease is intermittent claudication: a deep, cramping pain in the calves, thighs, or hips that occurs during physical activity and resolves within minutes of rest. Unlike general muscle soreness, this pain follows a predictable pattern tied directly to exertion.

This predictable discomfort occurs because narrowed arteries cannot deliver enough oxygen-rich blood to meet the increased demand of working muscles. Additional warning signs of arterial blockage include:

• Numbness or weakness in the legs
• Coldness in one foot or lower leg compared to the other
• Non-healing sores on the toes, feet, or legs
• Changes in skin color on the legs
• Diminished or absent pulse in the feet

Smoking, diabetes, high blood pressure, and high cholesterol are the primary risk factors that accelerate arterial narrowing. Because the circulatory system is entirely connected, PAD in the legs often signals that arteries near the heart and brain may also be affected. Reduced ABI values in patients with documented indications give physicians objective data to guide management.

What does a high ABI score above 1.40 mean?

An ABI score above 1.40 does not indicate superior circulation. Instead, it typically signals arterial calcification — a condition where the vessel walls have become rigid and resist compression by the blood pressure cuff. This produces an artificially inflated reading known as a false high.

Patients with diabetes, advanced chronic kidney disease, or long-standing hypertension are most likely to have calcified arteries. Because the stiffened vessel requires significantly more cuff pressure to compress, the machine records a higher-than-actual pressure reading. This means a falsely elevated ABI can mask underlying PAD that would otherwise produce a low score.

When ankle arteries are too calcified for accurate ankle brachial index measurement, physicians turn to the Toe Brachial Index (TBI) as an alternative diagnostic approach.

How Does the Toe Brachial Index Compare to the ABI?

The Toe Brachial Index (TBI) measures blood pressure in the big toe rather than the ankle, then compares it to arm pressure. The small digital arteries in the toes rarely calcify even when larger leg arteries have hardened, making the TBI a reliable alternative when standard ABI results are unreliable.

A normal TBI is generally 0.70 or above. Physicians typically order a TBI when:

• The initial ABI score exceeds 1.40, suggesting arterial calcification
• The patient has diabetes, which frequently affects larger leg arteries
• Unexplained foot pain or non-healing wounds are present despite a normal or high ABI

Advanced diagnostic platforms like the CMAT Advantage system measure both ABI and TBI in a single testing session, along with heart rate variability (HRV), sudomotor function, and additional autonomic nervous system markers. This comprehensive approach gives physicians a complete cardiovascular and neurological risk profile from one 7 to 10 minute, non-invasive test. Practices interested in adding these capabilities can learn more about implementation and reimbursement support.

How Should You Prepare for Your ABI Test?

Preparing for an ABI test requires minimal effort. Wear loose-fitting clothing that allows easy access to your ankles and upper arms. Avoid caffeine and tobacco for at least two hours before the test, as both temporarily constrict blood vessels and can produce inaccurate readings.

To get the most value from your appointment, consider asking your physician these questions:

• Is my exact ABI number within the normal ankle brachial index range of 1.00 to 1.40?
• Do these results suggest any hidden cardiovascular risk factors?
• Should we schedule a follow-up test, and if so, how frequently?
• What lifestyle changes would help protect my circulation long-term?

Keeping a personal record of your ABI results over time allows you and your physician to track trends and notice meaningful changes that may warrant attention. This longitudinal tracking of your normal ankle brachial index helps inform your care as part of managing vascular disease.

Frequently Asked Questions About the Normal Ankle Brachial Index

How often should you get an ABI test?

The American Heart Association recommends ABI testing for adults over 65, anyone over 50 with a history of smoking or diabetes, and individuals with symptoms of leg pain during walking. If your initial results are normal, your physician decides whether and when to repeat the test based on your symptoms and risk factors. Patients with borderline results (0.91-0.99) should be discussed with their physician about how often to repeat the test.

Can you improve a low ABI score?

Yes. Smoking cessation, regular walking exercise (30-45 minutes daily), blood pressure management, cholesterol control, and diabetes management can all help improve peripheral blood flow over time. Studies show that supervised exercise programs may improve walking distance in patients with mild to moderate PAD.

Is an ABI test covered by Medicare and insurance?

ABI testing is covered by Medicare when medically indicated. The test is typically billed under CPT code 93923, with reimbursement that varies by the complexity of the study, payer, and the additional measurements performed.

What is the difference between ABI and ankle blood pressure?

Ankle blood pressure is a raw measurement of systolic pressure at the ankle, expressed in mmHg. The ankle brachial index is a ratio that divides the ankle pressure by the arm pressure, producing a dimensionless number (typically between 1.00 and 1.40 for healthy individuals). The ratio format normalizes the measurement, making it more clinically meaningful than ankle pressure alone.

What are normal ABI values?

Normal ABI values fall between 1.00 and 1.40. On the standard AHA/ACC scale, 1.00 to 1.40 indicates healthy circulation, 0.91 to 0.99 is borderline, 0.41 to 0.90 indicates mild to moderate peripheral artery disease (PAD), 0.40 or below indicates severe PAD, and above 1.40 indicates noncompressible, calcified arteries.

What ABI value is considered abnormal?

An ABI of 0.90 or below is abnormal and indicates peripheral artery disease (PAD). A value above 1.40 is also abnormal — it usually reflects arterial calcification, which produces a falsely high reading rather than better-than-normal circulation. In that situation physicians follow up with a toe-brachial index (TBI), where a value of 0.70 or above is considered normal.

What ABI value indicates PAD?

An ankle-brachial index of 0.90 or lower indicates peripheral artery disease (PAD). Values from 0.41 to 0.90 reflect mild-to-moderate PAD, and 0.40 or lower reflects severe PAD. An ABI above 1.40 is also abnormal but reflects noncompressible, calcified arteries rather than PAD, and is evaluated with a toe-brachial index.

Take the Next Step for Your Vascular Health

Understanding your normal ankle brachial index is a straightforward, evidence-based step toward protecting your long-term cardiovascular health. Whether your results confirm healthy circulation or identify areas that need attention, the ABI gives you and your physician a clear foundation for informed decision-making.

Is there an ICD-10 code for an abnormal ABI?

No. An abnormal ankle-brachial index is a test finding, not a diagnosis, so ICD-10-CM has no code for the result itself. The physician records the confirmed vascular condition or the symptom that prompted the study, such as peripheral vascular disease (I73.9) or atherosclerosis of the extremities with intermittent claudication (I70.21-). An abnormal reading on its own, with no documented symptom or indication, does not establish medical necessity, and the diagnosis codes Medicare accepts vary by contractor, so confirm the covered list in your MAC policy. Our ABI CPT 93923 billing guide walks through the ICD-10 pairings and documentation in full.

For physicians interested in adding comprehensive ABI, TBI, and autonomic nervous system testing to their practice, HealthWright Technologies provides the FDA-cleared CMAT Advantage diagnostic system along with full training, implementation support, and billing guidance. Contact HealthWright Technologies at (678) 322-7146 or visit healthwrighttechnologies.com to learn how the CMAT Advantage can enhance your diagnostic capabilities.

Disclaimer: This article is for informational and educational purposes only and does not constitute medical advice. Always consult a qualified healthcare provider for diagnosis and treatment decisions. HealthWright Technologies provides diagnostic equipment to physicians and does not provide clinical services.

CPT codes are provided for informational purposes only and do not guarantee reimbursement. Verify code applicability and coverage with the relevant payer and your billing department before submitting claims. CPT® is a registered trademark of the American Medical Association.