Approximately 20 to 30 percent of adults in the United States may not be correctly diagnosed with having hypertension due to differences in their blood pressure when measured in their doctor’s office versus outside of their doctor’s office. This condition, masked hypertension occurs when people do not have high blood pressure based on readings measured in their doctor’s office, but they have high blood pressure readings when measured outside of a clinical setting.

While many people have heard of white coat hypertension, a syndrome where one has a high blood pressure reading when taken at the doctor’s office, but normal when measured outside of a clinical setting, data on masked hypertension have only been published over the past 15 to 20 years, according to Paul Muntner, PhD, lead author of the latest scientific statement on blood pressure measurement from the American Heart Association and an epidemiologist at the University of Alabama at Birmingham School of Public Health.