On Oct. 9, 2024, a study led by Johns Hopkins Medicine researchers concluded that commonly used ways of positioning the patient’s arm during blood pressure (BP) screenings can substantially overestimate test results and may lead to a misdiagnosis of hypertension.

investigators examined the effects of three different arm positions: an arm supported on a desk, arm supported on a lap, and an unsupported arm hanging at the patient’s side. Researchers found that lap support overestimated systolic pressure (the top number in a BP reading) by nearly 4 mmHg, and an unsupported arm hanging at the side overestimated systolic pressure by nearly 7 mmHg.

According to the American Heart Association, nearly half of U.S. adults have elevated blood pressure, a diagnosis made when the measured force of blood flowing through blood vessels is higher than what is generally considered normal, on average 120/80. The study findings were published in JAMA Internal Medicine.