CPT Code for Ankle Brachial Index

Let’s be honest for a second. Medical coding can sometimes feel like trying to read a map in the dark.

If you are a medical biller, a clinician, or even a curious patient, finding the right CPT code for ankle brachial index testing can be confusing. You see different numbers online. You hear conflicting advice from colleagues. And you worry about denials.

I have been there. And I am here to help you clear up the confusion.

This guide is not a copy-paste from a coding manual. It is a realistic, human-written resource designed to help you understand exactly which code to use, when to use it, and how to avoid common mistakes.

We will keep the language simple. We will use tables and lists to make everything clear. And by the end, you will feel confident selecting the correct code for every patient scenario.

Table of Contents

What Is an Ankle Brachial Index? A Quick Refresher

Before we talk about codes, let us quickly cover the test itself. You probably already know this, but a quick reminder helps put the coding rules into context.

The Ankle Brachial Index (ABI) is a simple, non-invasive test. It helps doctors check for Peripheral Artery Disease (PAD).

Here is how it works in plain English:

A technician takes blood pressure readings in the patient’s arms (usually both).
They also take pressure readings at the ankles (usually over the posterior tibial and dorsalis pedis arteries).
Then, they divide the highest ankle pressure by the highest brachial (arm) pressure.

The result is a number. That number tells the doctor how well blood is flowing to the legs.

Normal ABI: 1.0 to 1.4
Mild to Moderate PAD: 0.5 to 0.9
Severe PAD: Below 0.5

Now, you might be thinking: “That sounds simple. Why are there multiple CPT codes for that?”

Great question. The answer lies in how the test is performed and how many pressure measurements are taken. Let us unpack that.

The Core CPT Codes for Ankle Brachial Index (ABI)

The American Medical Association (AMA) has three main CPT codes for non-invasive peripheral arterial studies. Not all of them are appropriate for every ABI.

Here are the codes you need to know:

CPT Code	Official Descriptor (Simplified)	Typical Use Case
93922	Unilateral or limited study (1-2 levels)	One limb, or only ankle pressures without waveforms
93923	Bilateral or complete study (3+ levels)	Both legs, multiple pressures + waveforms (most standard ABIs)
93924	With exercise (before and after)	ABI performed at rest and again after treadmill walking

Important Note for Readers: Do not use CPT code 93922 for a standard, bilateral ABI. That is one of the most common reasons for denials. Keep reading to learn why.

Let us explore each of these codes in detail.

CPT 93922: Unilateral or Limited Study (The Partial Test)

When to Use 93922

CPT 93922 is the “limited” code. You use it when the provider only performs a partial study.

Typical scenarios include:

Only one leg is tested (unilateral).
Only 1 to 2 levels of pressure are taken per leg.
The provider does not record pulse volume recordings (PVRs) or waveforms.
A quick screening test where only ankle pressures are measured, but no arm comparisons are documented.

In simple terms: If the work is minimal and not truly diagnostic, 93922 might be the right choice.

Realistic Example for 93922

A 78-year-old man comes in with a non-healing ulcer on his right great toe. The doctor only wants to check the right ankle pressure to get a quick baseline. No waveforms are recorded. No left leg pressures are taken. Only two pressures are measured on the right ankle.

Likely code: 93922

A Word of Caution

Many payers consider 93922 a “screening” level of service. Reimbursement is low. Some commercial insurers do not reimburse it at all unless medical necessity is clearly documented.

If you are doing a complete ABI with both arms and both ankles, do not use 93922. You will leave money on the table, or worse, get a denial for “incorrect coding.”

CPT 93923: Complete Bilateral Study (The Standard ABI)

This is the workhorse code. When most people ask for the cpt code for ankle brachial index, they are actually looking for 93923.

When to Use 93923

You should report 93923 when the provider performs a complete, bilateral, non-invasive peripheral arterial study.

Requirements usually include:

Both legs are evaluated (bilateral).
Three or more levels of pressure are recorded.
Waveforms or pulse volume recordings (PVRs) are documented.
Segmental pressures are measured (thigh, calf, ankle, etc.).
The test includes resting pressures and waveforms.

Realistic Example for 93923

A 65-year-old woman with diabetes and a history of smoking complains of calf pain when walking. The doctor orders a standard bilateral ABI. The vascular tech places cuffs on both arms, both thighs, both calves, and both ankles. They record segmental pressures and pulse volume recordings at each level. They calculate the ABI for both legs.

Likely code: 93923

What About Doppler Waveforms?

Here is a key detail. Many coders ask: “Do we need to document waveforms for 93923?”

The short answer is yes. For 93923, the standard of practice includes both segmental pressures and waveform analysis (usually PVRs). If your provider only records ankle pressures without waveforms, some auditors would say 93922 is more appropriate.

Always check your payer policies. But in general, 93923 = full study with waveforms.

CPT 93924: With Exercise (The Stress Test)

When to Use 93924

Sometimes a patient has a normal ABI at rest. But they still have classic leg pain with walking. In that case, the doctor might order an exercise ABI.

Here is the process:

The provider performs a complete resting ABI (like 93923).
The patient walks on a treadmill (usually at a set speed and incline) for 5 minutes or until symptoms appear.
Immediately after exercise, the provider repeats the ABI measurements.
The results are compared to see if there is a drop in pressure (which suggests PAD).

Realistic Example for 93924

A 55-year-old man has normal resting ABIs (1.1 bilaterally). But he reports severe calf tightness after walking two blocks. His doctor orders an exercise ABI. After 5 minutes on the treadmill, his right ankle pressure drops from 140 mmHg to 90 mmHg. That confirms functional PAD.

Likely code: 93924

Important Billing Note

CPT 93924 includes the resting study. You cannot bill 93923 and 93924 for the same visit. The exercise code is all-inclusive. Also, you need to report a separate CPT code for the treadmill test (usually 93015 or 93018 for cardiovascular stress testing) depending on the payer.

Comparative Table: 93922 vs 93923 vs 93924

Let us make this even clearer. Here is a side-by-side comparison.

Feature	93922	93923	93924
Number of limbs	Unilateral (one leg)	Bilateral (both legs)	Bilateral (both legs)
Number of levels	1-2 levels	3 or more levels	3 or more levels
Waveforms (PVRs)	Usually not recorded	Always recorded	Recorded at rest & post-exercise
Treadmill exercise	No	No	Yes
Typical reimbursement	Low	Moderate to high	Highest (due to complexity)
Common denials	Billed as bilateral	Missing waveforms	Missing exercise documentation

Common Billing Mistakes (And How to Avoid Them)

Even experienced coders make errors. Let me walk you through the most frequent mistakes I see with the CPT code for ankle brachial index.

Mistake #1: Billing 93922 for a Bilateral Study

I cannot stress this enough. If you do a bilateral ABI with four or more pressures and waveforms, 93923 is the correct code. Billing 93922 for a full study is technically incorrect. It also pays less.

How to avoid: Always count the number of levels documented. More than 2 levels? Do not use 93922.

Mistake #2: Forgetting the Waveforms for 93923

Remember what I said earlier. 93923 expects segmental pressures and waveforms. If your provider only records pressures, some auditors will downgrade the code to 93922.

How to avoid: Review your documentation templates. Ensure waveform analysis is clearly mentioned in the report.

Mistake #3: Not Modifying for Reduced Services

Sometimes a patient cannot tolerate a full bilateral study. For example, a patient with an amputation or a severe wound on one leg. In that case, you might append modifier -52 (Reduced Services) to 93923.

How to avoid: If only one leg is tested due to medical reasons, do not default to 93922. Use 93923 with modifier -52 and explain why in the notes.

Mistake #4: Billing 93924 Without Proper Exercise Documentation

Payers want proof. Your report must include:

The duration of exercise (e.g., “5 minutes at 2 mph, 10% grade”)
The reason the test was stopped (e.g., “Patient stopped due to leg pain”)
Pre-exercise pressures and waveforms
Post-exercise pressures and waveforms

Without these four elements, expect a denial.

What the Guidelines Say (Without the Legal Jargon)

I am not going to copy-paste the entire CPT manual here. That would be boring and unrealistic. But I will summarize what the official guidelines tell us.

The CPT guidelines for non-invasive vascular studies state that you should code based on:

Extent of the study (limited vs complete)
Number of levels (1-2 vs 3+)
Use of waveforms (with or without)
Physiological challenges (exercise or post-occlusive reactive hyperemia)

Also, note that these codes (93922-93924) are for physiological studies. They are different from duplex ultrasound codes (93970, 93971), which look at actual blood flow images. Do not confuse the two.

Reader Note: If your provider uses a Doppler probe to listen to flow but does not record waveforms, that is usually still a physiological study. If they take actual images of the artery, that is duplex. Different codes entirely.

How to Document an ABI for Correct Coding

Good documentation leads to correct coding. Period. Here is a simple checklist for your providers or your own records.

Required Elements for 93923 (Standard Bilateral ABI)

Resting brachial pressures (both arms)
Resting ankle pressures (both ankles, typically two arteries per ankle)
Segmental pressures (at least three levels: high thigh, low thigh, calf, or ankle)
Pulse volume recordings (waveforms) at each level
Calculation of ABI ratio for each leg
Interpretation by a qualified provider

Required Elements for 93924 (Exercise ABI)

All elements of 93923 at rest
Treadmill protocol description (speed, grade, duration)
Patient’s symptoms during exercise
Immediate post-exercise pressures (same levels as rest)
Post-exercise waveforms
Comparison of pre and post values

Payer-Specific Considerations (Medicare, Commercial, etc.)

I have to be honest with you. Not all payers follow the same rules. What works for Medicare might not work for Blue Cross. Let me give you a realistic overview.

Medicare (National Coverage Determination)

Medicare covers ABI testing for patients with suspected PAD when certain criteria are met. For coding:

Medicare generally expects 93923 for a complete bilateral study.
They rarely reimburse 93922 for a full study.
For exercise ABI (93924), Medicare requires specific documentation of symptoms and a supervised treadmill test.

Pro tip: Check your local MAC (Medicare Administrative Contractor). Some have local coverage determinations (LCDs) with specific requirements for waveforms.

Commercial Payers (UnitedHealthcare, Aetna, Cigna, etc.)

Most commercial payers follow CPT guidelines closely. However:

Some require prior authorization for 93924.
Others consider 93922 a “non-covered” service for routine screening.
A few bundle 93923 with an office visit (so do not append modifier -25 unless appropriate).

Pro tip: When in doubt, call the payer. Yes, it takes time. But it saves denials.

Workers’ Compensation

Workers’ comp cases are different. If a patient has a work-related injury that affects the legs, and the ABI is part of that claim, use the same codes. But check your state’s fee schedule. Some have unique reimbursement rates.

Real-Life Coding Scenarios (With Answers)

Let us put your knowledge to the test. Here are six realistic patient scenarios. Cover the answers and see if you match mine.

Scenario 1

A 72-year-old man with diabetes and a 10-year history of smoking. His doctor orders a bilateral ABI to screen for PAD. The tech records brachial pressures, ankle pressures (both ankles), and calf pressures. Waveforms are recorded at each level. A full report with ratios is generated.

Your code?

Answer: 93923. This is a complete bilateral study with three or more levels and waveforms.

Scenario 2

A 50-year-old woman with a right leg wound. The doctor only wants to rule out PAD in the right leg. The tech records ankle pressures on the right only. No waveforms. No left leg pressures. Only two pressure readings.

Your code?

Answer: 93922. Unilateral, limited to 1-2 levels, no waveforms.

Scenario 3

A 60-year-old man with normal resting ABIs but classic claudication. He walks on a treadmill for 4 minutes until his calf hurts. Post-exercise pressures drop by 25 mmHg. The report includes pre and post waveforms.

Your code?

Answer: 93924. Exercise ABI.

Scenario 4

A patient has a bilateral ABI. The provider documents pressures at both arms, both ankles, and both calves. However, the report does not mention waveforms or PVRs at all.

Your code?

Answer: This is tricky. Some auditors would say 93922 because waveforms are missing. Others would allow 93923 if the provider intended a complete study. Best practice: Ask the provider to add waveform documentation. If not possible, 93922 is safer.

Scenario 5

An 85-year-old patient has a left below-knee amputation. The doctor orders an ABI on the remaining right leg only. The tech records brachial pressures, right ankle pressures, and right calf pressures with waveforms.

Your code?

Answer: 93923 with modifier -52 (Reduced Services). Why not 93922? Because you have three levels and waveforms. Modifier -52 tells the payer the bilateral study was medically reduced to unilateral.

Scenario 6

A provider performs an ABI in the office using a handheld Doppler. They listen to flow at both arms and both ankles. They write down the pressures. They do not print any waveforms. They calculate the ratio.

Your code?

Answer: Many coders would say 93922 (limited, no waveforms). Some payers do not reimburse this at all. If your payer requires waveforms for any ABI code, this would be non-covered. Know your payer.

Frequently Asked Questions (FAQ)

Here are the questions I hear most often from readers just like you.

Q1: What is the most common CPT code for ankle brachial index?

A: The most common code for a standard, complete bilateral ABI is 93923. If you are only testing one leg or doing a quick screen without waveforms, use 93922.

Q2: Can I bill 93922 and 93923 together?

A: No. These codes are mutually exclusive. Choose the one that best describes the extent of the study. You cannot bill both for the same patient on the same day for the same condition.

Q3: Does Medicare cover ABI testing?

A: Yes, Medicare covers ABI testing when medically necessary for the diagnosis of PAD. However, coverage rules vary by local MAC. Always check your local coverage determination (LCD).

Q4: What is the difference between 93923 and 93970?

A: Great question. 93923 is for physiological studies (pressures and waveforms). 93970 is for duplex ultrasound (real-time images of the artery with color flow). They are different tests. Do not confuse them.

Q5: Do I need a modifier for a unilateral ABI?

A: If you are billing 93923 for a bilateral study but only performed it on one leg due to medical reasons (amputation, cast, wound), use modifier -52. If you performed a truly limited study (1-2 levels, no waveforms), use 93922 instead.

Q6: How many levels are required for 93923?

A: The CPT manual says “3 or more levels.” Typically, that means at least high thigh, calf, and ankle. Some payers accept low thigh, calf, and ankle. Check your payer policy.

Q7: Is a provider interpretation required?

A: Yes. For any of these codes, the report must include an interpretation by a qualified provider (MD, DO, NP, PA, or certified vascular specialist depending on state law). Without an interpretation, you are billing a technical component only (modifier -TC).

Q8: Can a medical assistant perform the ABI?

A: It depends on state scope of practice and payer rules. For the technical component (performing the test), trained staff may do it under supervision. For the professional component (interpretation), a licensed provider must do it. Never bill for an interpretation that was not actually performed by a qualified provider.

Q9: What if the patient cannot tolerate a full bilateral study?

A: Document why. For example: “Patient refused left leg due to pain.” Then, use the code that matches what you actually performed. If you did three levels with waveforms on one leg only, use 93923 with modifier -52.

Q10: How much does Medicare pay for 93923?

A: I cannot give you an exact number because fees vary by region and year. But as a rough estimate, the national average allowed amount for 93923 (facility price) is between $60 a n d$ 60and120. The non-facility price (office-based) is higher because it includes equipment and overhead. Always check the current Medicare Physician Fee Schedule.

Tips for Reducing Denials

Nobody likes denials. They cost time and money. Here are five practical tips to keep your claims clean.

1. Double-Check Medical Necessity

Before you submit a claim for an ABI, ask yourself: Does this patient have signs or symptoms of PAD? The medical record should clearly state why the test was needed.

Good: “Patient reports bilateral calf pain when walking 2 blocks.”
Bad: “Screening for vascular disease” (without symptoms – many payers deny this).

2. Use the Correct Modifiers When Needed

Modifiers are not scary. They just tell the payer more information.

-52 (Reduced services): For a complete study that is partially performed (e.g., unilateral due to amputation).
-TC (Technical component): If you only did the test but someone else interprets it.
-26 (Professional component): If you only interpreted the test but someone else performed it.
-59 (Distinct procedural service): Rare for ABI, but used if you perform an ABI and another vascular study on the same day that is not normally bundled.

3. Ensure Waveform Documentation for 93923

I have said this before, but it is worth repeating. If your report does not include waveforms, do not bill 93923. Either add the waveforms or use 93922.

4. Do Not Unbundle

Some coders try to bill multiple units of 93922 (one per leg). Do not do that. CPT guidelines say to report only one unit of the code that describes the entire study. Unbundling is a compliance risk.

5. Stay Updated

CPT codes change. Payer policies change. Make it a habit to review your top 20 codes (including 93922, 93923, and 93924) every year before January 1. A few minutes of review can save months of denials.

The Patient Perspective: Explaining the ABI and Its Cost

Since you are a reader-focused writer (and I am a reader-focused writer), let me briefly step into the patient’s shoes.

If a patient asks you, “What is the CPT code for ankle brachial index?” they are probably not a coder. They are probably a patient looking at their medical bill.

Here is what you can tell them in plain English:

“The Ankle Brachial Index is a painless test that compares blood pressure in your arms to blood pressure in your ankles. It helps your doctor find blockages in your leg arteries. The billing code for this test is usually 93923 if both legs are tested. Your insurance may cover it if your doctor ordered it for a medical reason, like leg pain or a non-healing wound.”

That is transparent. That is honest. And that is helpful.

Additional Resources for Readers

I promised you an additional resource. Here it is.

Conclusion

Summary of this article:
You now know that CPT 93923 is the standard code for a complete bilateral ankle brachial index with waveforms, while 93922 is for limited or unilateral studies. CPT 93924 adds an exercise component for patients with normal resting ABIs but leg pain with walking. Always document waveforms for 93923, avoid common billing mistakes like undercoding or unbundling, and check payer policies before submitting claims.