Nearly half of adults in the United States have hypertension.  This is usually managed well by primary care physicians.  However, some people have a harder time with blood pressure control despite multiple medications, and they may benefit from evaluation by the nephrologist.  In some people, overactive hormones, or even structural issues such as plaque in the kidney artery may be the cause of uncontrolled high blood pressures.  Evaluation by the nephrologist can help manage hypertension better, which ultimately will lead to protecting kidney function.  Part of your evaluation may include a 24 hour blood pressure monitor.  This is a portable blood pressure monitor which you will go home with, and bring back the next day.  The data will provide critical information to better assess your blood pressure trends, which may be important in finding the right regimen of medications to treat your high blood pressure.