A difference greater than about 10–15 mmHg between arms indicates what action?

• A. Use the arm with the lower reading for subsequent measurements
• B. Use the arm with the higher reading for subsequent measurements and confirm
• C. Ignore the difference and continue with the standard protocol
• D. Repeat measurements on the same arm only

Answer: (B)

When two arms show a systolic blood pressure difference of about 10–15 mmHg or more, it signals that the arms may not reflect the same vascular pressures, which can be due to arterial disease or measurement variability. The best action is to use the arm with the higher reading for subsequent measurements and confirm with repeat checks. Using the higher arm helps avoid underestimating a true elevated blood pressure, which is important for accurate diagnosis and treatment decisions. It also provides a consistent reference when monitoring over time. To confirm the finding, you should repeat measurements, ideally on both arms, with proper technique and the same cuff size, to ensure the difference is real and not due to error. If the higher reading persists, document it and consider further evaluation for possible vascular issues. Choosing the arm with the lower reading would risk underestimating BP, ignoring the difference could miss a vascular problem, and repeating on the same arm does not address the inter-arm discrepancy.