I've been attending Hypertension Clinics here in the UK for some years.
Due to 'white coat syndrome' it was felt surgery BP checks were unreliable.

So, now they regularly monitor me over a full 24hr period.
I get to wear a belt pack and cuff that will randomly record BP as I go about my life.
A more intense check will require you to keep a diary of activities for the time monitored.

Mike