Generally a small difference in blood pressure reading between arms is not a health concern.However,a difference of not more than 20 millimeters of mercury (mmhg) for systolic pressure(top number)or more than 10 mmhg.for diastolic pressure(bottom number)may be sign of an underlying problem -------such as narrowing of the main arteries to that arm.If you have a significant difference in blood pressure readings between arms,talk to your doctor.
A difference of 10-15 mmhg for systolic pressure that shows up repeatedly is a risk marker for vascular disease and for greater risk of developing cardiovascular disease and related complications during the next 10 years.
Your doctor may measure your blood pressure in both arms,to see if you have high blood pressure(hypertension),if your blood pressure is higher in one arm,your doctor will probably use the blood pressure reading from that arm to monitor your blood pressure.
A large difference in blood pressure measurement between your arms could signal a health problem,such as
Blocked arteries,
Kidney disease
Diabetes
Heart defects.