8th March 2024

Diagnosing hypertension

NICE recommends that blood pressure is measured in a relaxed, temperature setting with the person quiet, seated with their arms outstretched and supported. Whilst most of these factors can be addressed in the clinic, it is natural for some patients to have raised blood pressure in the presence of a medical professional and this is known as white coat hypertension. When blood pressure is raised between 140/90 mmHg and 180/120 mmHg, further ambulatory blood pressure monitoring (ABPM) should be offered to confirm the diagnosis. ABPM involves wearing a device which measures blood pressure over a 24-hour period. If this is unsuitable or the person is unable to tolerate it, home blood pressure monitoring (HBPM) is advised where the patient takes their own reading, ideally twice a day for a week. 

If the clinic blood pressure reading is >180/120 mmHg, then referral for same-day specialist assessment is warranted in the presence of retinal haemorrhage/papilledema, acute kidney injury, new confusion, chest pain or signs of heart failure.  If there are no signs to indicate same day referral, then further investigation to identify possible target organ damage should be conducted. 

These cut-offs and guidelines can get confusing, therefore the image below outlines the algorithm for diagnosing hypertension, which some readers may find easier to digest.  

Image Source: NICE (2019). visual-summary-pdf-6899919517, Licensed under a creative commons licence. Available for free at: https://www.nice.org.uk/guidance/ng136/resources/visual-summary-pdf-6899919517 (Accessed: 26 January 2024).