The National Institute for Health and Clinical Excellence (NICE) is considering changing how people's blood pressure is checked on the NHS.
The proposals would see people with blood pressure measurements of 140/90 mmHg or higher sent home for 24 hours.
Patients can become anxious in the waiting room, with "white coat" syndrome sending their blood pressure up.
Measuring their blood pressure at home using ambulatory blood pressure monitoring (ABPM) or home blood pressure monitoring (HBPM) would give doctors a more accurate reading, according to NICE.
The draft guidance, which is open to consultation, could reduce the number of people under 40 who are diagnosed with high blood pressure.
However, doctors are being urged to ensure they look at the lifetime possibility of heart attack or stroke when deciding to exclude a person from treatment.
There are more than 8.5m people in the UK diagnosed with high blood pressure but many more are undiagnosed.
In 2008, 32% of men and 29% of women in England had high blood pressure (defined as a systolic blood pressure of 140 mmHg or over, or a diastolic blood pressure of 90 mmHg or over) or were being treated for the condition.
"Regardless of age, using a standard hypertension protocol, all patients need to be identified, monitored and helped with encouragement of dietary or life style changes, supported with medication if needed and given the necessary care. This is nothing new. Reducing the numbers for statistics doesn't give a picture of a healthy nation! Sending someone home for 24 hours doesn't lower a reading. What has happened to common sense? "White coat syndrome" is not a common phenomenon. These patients will be identified through good communication when the BP is monitored. My BP is going up reading the above article ... What of that! Come on!" - Anne, Swindon
"This not new in general practice, but the facilities were not adequate to go round all pt. with elevated blood pressure" - L Fox-Cobham
"Brilliant! And a bit old hat!!! We have been doing 24 ambulatory BP recordings for at least the last 10 years!! Where has everyone else been!!" - Polly Filby, Chelmsford
"Excellent idea. Very wise proposal as my husband suffers from white coat syndrome and last GP check of his B/P had him being warned/threatened he would be hospitalised next time !!So I welcome this immensely as a nurse and a wife" - Linda McCrea, Belfast
"We have about 10 B/P machines which are loaned out before treatment is initiated. It gives a much better idea of what the B/P is really like" - Jane, Cambs