Its a phenomonen called white coat hypertension. Its like a nervous reaction to having it taken! You could go have a 24 hour ABPM test. Its non invasive, slightly cumbersome but will give proper reading for the 24 hours. They allow 1 - 2 hours at start and finish for the fear factor and the middle 20 hours is used to average the BP. So go have it. I blamed White coat for my high readings for years!!! IT was high all the time!