It sounds like you've had an ambulatory BP monitor study. All this does is record your blood pressure over a period of 24 hours. This gives us a more accurate analysis of your blood pressure over a period of time. Single readings are very inaccurate.
This will also allow your Doctor to see how your blood pressure changes throughout the day. Your Doctor may have ordered this test to find out if you have high blood pressure
. Perhaps you visited your GP and a single reading was quite high. This can sometimes be explained by "white coat effect". The 24 hour BP monitor will diagnose or exclude hypertension
Another reason why the test is sometimes ordered is if you have already been diagnosed with hypertension and your GP simply wants to see how well your medicines are working. Or your Doctor may want to see if your blood pressure stays high at night. If this is the case, he might want to alter your medication.
Either way, it's nothing to worry about. Your Doctor will discuss the results with you.