diagnosis of prehypertension in children requires also three readings on 3 separate visits or in this case, repetitions can be done in the same visit?...

A diagnosis of prehypertension in children requires also three readings on 3 separate visits or in this case, repetitions can be done in the same visit? In the Fourth report in some parts they tell about repeating in the same visit if in the range of prehypertension but in other parts they say that it should be on 3 different visits, and I'm confused. Thank You for your help.