What do different blood pressure readings on the left & right arms mean?

Updated March 23, 2017

The blood-pressure cup releases and the reading shows a slightly elevated blood pressure. The other arm shows a blood pressure higher than the first. Images of heart attacks, blood clots and all sorts of vascular problems go through your head. You wonder what causes this and whether you should be concerned.

Different Readings

Inter-arm blood-pressure difference is a variation in blood-pressure readings between the right and left arms. This is often picked up by people taking their own blood pressure, but may be found during an exam.

Normal Variation

Inter-arm blood-pressure differences are not unusual. A variation of up to 10 mm Hg in either systolic or diastolic pressures is common, and the larger number is usually that of the dominant arm. For example, a right-handed person should expect the right arm reading to be slightly higher than the left.

Be Concerned

While a variation between left- and right-arm blood pressures of less than 10 mm Hg is usually not of concern, a physician should be notified if the difference is greater. Some of the potential problems associated with a large IAD include peripheral vascular disease, increased risk of death associated with some conditions and pregnancy complications.

PVD Indicator

A study done by Clark, Campbell, Powell and Thompson showed a higher prevalence of IAD among patients with asymptomatic peripheral vascular disease. This is an indicator that should not be ignored, because of increased risk of heart attacks and other cardiovascular crisis.

Kidney Disease

In a 2008 study, Agarwal, Bunaye, and Bekele found that every 10 mm Hg systolic difference was associated with a 24 per cent higher rate of death in patients with chronic kidney disease.

IAD in Pregnancy

Blood pressure in pregnant women shows a significant difference in inter-arm blood pressure, according to a 2008 study by Poon, Kametas, Strobl, Pachoumi and Nicolaides. Their findings showed that increases in hypertension among pregnant women also increased the IAD significantly, which could mask a jump in blood pressure if testing on only one arm.


The researchers recommend that medical professionals get a blood pressure reading from each arm, record which arm reads higher and use that arm for subsequent readings. In pregnant women, they recommend getting a blood-pressure reading from each arm at every visit. IAD should also be measured regularly in patients at risk for cardiovascular conditions.

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About the Author

Kim Scott has been writing professionally and personally for over 10 years. She holds a degree in graphic design and printing management from Pittsburg (KS) State University and has graduate level-education in Early Childhood Education.