Sue - IF the BP was a one-off in the doctor's consulting room, then forget it. Get yr own monitor - upper cuff. Get a good one, otherwise a total waste of money.
Take BP 3xper diem, times 3 times, each arms, and do for three days. SO, will have 18 readings in total for each day. Then, take the average for each. So, will have three average readings for each arm for each day. After three days, then take a further average, separate for each arm. Now, go visit the doctor with yr numbers - or send em into him?
Set monitor back to off, and loosen cuff between each reading take.
Some cardiologists (and doctors) often discard the first of the 3x reading. Suggesting/of the opinion that the first reading is not that accurate. So you can do a second set of numbers, discarding the first reading. My doctor takes all three into consideration, my cardi prefers to set aside the first readings, only taking into consideration the second and third and using the 2&3 to make his averages. But if they have full sight of all the numbers involved then their judgement call.
Alternative, go on a 24hr monitor.
Mission not impossible!