Which step is part of performing an ABI exam?

• A. Apply Doppler gel
• B. Inflate cuff to 100 mmHg above systolic
• C. Place the probe at a 90-degree angle toward the elbow
• D. Record the systolic pressure of only one arm

Answer: (A)

Applying Doppler gel is essential in an ABI exam because the Doppler device relies on good acoustic coupling between the transducer and the skin to hear arterial flow signals clearly. The gel fills tiny air gaps that would otherwise block the ultrasound waves, enabling accurate detection of systolic waveforms as you measure pressures in the brachial and ankle arteries.

Other choices don’t fit the technique: inflating the cuff to 100 mmHg above systolic is too high for a standard ABI maneuver—typically you inflate just enough (about 20–30 mmHg above systolic) to occlude flow and then gradually deflate to get the systolic pressure. Placing the probe at a 90-degree angle toward the elbow isn’t correct because the transducer should lie along the artery’s course with a small, appropriate angle to optimize signal, not perpendicular. Recording the systolic pressure of only one arm omits essential data—ABI requires measurements from both arms (and both ankles) to determine the appropriate reference pressures for calculating the index.