AdvertisementOdds Are, They're Taking Your Blood Pressure All WrongNovember 20, 2017Richard HarrisfacebookEmailEmily Blair, a medical assistant at the Colon, Stomach and Liver Center in Lansdowne, Va., takes a blood pressure reading for Robert Koenen. New guidelines say that patients should have their arm resting on a surface while taking a reading and both feet should be placed flat on the ground. (Josh Loock/NPR)