See the British and Irish Hypertension Society's website for a list of validated blood pressure monitoring devices. [2004] 1.1.4 When measuring blood pressure in the clinic or in the home, standardise the environment and provide a relaxed, temperate setting, with the person quiet and seated, and their arm outstretched and supported. Use an appropriate cuff size for the person's arm. [2011, amended 2019] 1.1.5 In people with symptoms of postural hypotension (falls or postural dizziness): measure blood pressure with the person either supine or seated measure blood pressure again with the person standing for at least 1 minute before measurement. [2004, amended 2011] 1.1.6 If the systolic blood pressure falls by 20 mmHg or more when the person is standing: review medication measure subsequent blood pressures with the person standing consider referral to specialist care if symptoms of postural hypotension persist. 1.2 Diagnosing hypertension 1.2.1 When considering a diagnosis of hypertension, measure blood pressure in both arms: If the difference in readings between arms is more than 15 mmHg, repeat the measurements. If the difference in readings between arms remains more than 15 mmHg on the second measurement, measure subsequent blood pressures in the arm with the higher reading. [2019] 1.2.2 If blood pressure measured in the clinic is 140/90 mmHg or higher: Take a second measurement during the consultation. If the second measurement is substantially different from the first, take a third measurement. Record the lower of the last 2 measurements as the clinic blood pressure. 1.2.3 If clinic blood pressure is between 140/90 mmHg and 180/120 mmHg, offer ambulatory blood pressure monitoring (ABPM) to confirm the diagnosis of hypertension. See the section on identifying who to refer for people with a clinic blood pressure 180/120 mmHg or higher. 