The same as any other monitor. Your blood pressure levels will not change from monitor to monitor. If they do then there is something seriously wrong with you or with the monitor. 120/80 mm hg is the normal blood pressure for a human being and if it below or above it then you have a problem. Generally a high blood pressure is considered to be more of a problem than a low blood pressure level. But you have to get it checked out as soon as possible. The monitor is only a guide and it is better to let the professionals handle them.