Generally, a small difference in blood pressure readings between arms isn't a concern. But a difference of more than 10 millimeters of mercury (mm Hg) might cause worry. The difference can be in the top number, known as systolic pressure. Or it can be in the bottom number, known as diastolic pressure.

People who repeatedly have a blood pressure difference between arms of 10 to 15 mm Hg for systolic pressure are more likely to have vascular disease. They also have a greater risk of getting heart disease over time.

A repeated difference of more than 10 mm Hg in blood pressure measurement between the arms can be a sign of a health problem such as:

• Blocked arteries in the arms, known as peripheral artery disease.
• Diabetes.
• Kidney disease.
• Heart problem.

If you have a large difference in blood pressure readings between arms, talk to your health care provider. Your provider might use the arm with the higher reading to measure your blood pressure in the future.