ABI for each leg = the highest ankle pressure in that leg (dorsalis pedis or posterior tibial) divided by the highest of the two arm (brachial) pressures. The lower of the two legs is used to assess for peripheral arterial disease.
Enter systolic pressures (mmHg)
Right ABI
—
enter pressures
| > 1.40 | Non-compressible / calcified arteries — may be falsely high; consider a toe-brachial index (TBI) |
| 1.00 – 1.40 | Normal |
| 0.91 – 0.99 | Borderline (increased cardiovascular risk) |
| 0.71 – 0.90 | Mild peripheral arterial disease |
| 0.41 – 0.70 | Moderate peripheral arterial disease |
| ≤ 0.40 | Severe peripheral arterial disease |
How it is calculated & cautions
- Method (AHA): for each leg, take the higher of the dorsalis pedis and posterior tibial systolic pressures, and divide by the higher of the two brachial (arm) pressures.
- The lower-limb ABI governs the PAD assessment — report both, but the leg with the lower value is the one that defines disease.
- Also look at the absolute ankle pressure, not just the ratio. Focal disease (for example supplying an ulcer bed) can be missed by a near-normal overall ABI.
- ABI > 1.40 or non-compressible vessels (common in diabetes or chronic kidney disease) can give a falsely high or normal result — a toe-brachial index is advised.
- Resting ABI can be normal despite exertional symptoms; an exercise (treadmill) ABI may be needed.
Interpret in clinical context. This is a calculation aid, not a diagnosis.
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MBS item 11610 — measurement of ankle:brachial indices and arterial waveform analysis: bilateral Doppler or plethysmographic measurement of posterior tibial, dorsalis pedis (or toe) and brachial pressures, calculation of the ankle (or toe) brachial indices, and assessment of arterial waveforms for evaluating lower-extremity arterial disease, with examination, a
hard-copy trace and report. The descriptor carries
no specialist restriction, so a medical practitioner (including a GP) can claim it where the service is performed to the item requirements.
Schedule fee $74.30 (85% benefit ≈ $63.20) as at July 2026 — indexed annually on 1 July. Confirm the current fee and any rules on MBS Online before billing.
Sources. ABI method and interpretation: American Heart Association — Measurement and Interpretation of the Ankle-Brachial Index (
Circulation); consistent with USPSTF and ACC/AHA guidance. Billing: MBS Book (July 2026), item 11610 — verify the current fee on
MBS Online. Clinical reference for health professionals; interpret in context, not a diagnosis.