What are the recommended diagnostic criteria for hypertension in adults according to UK guidelines?

According to UK guidelines, the diagnosis of hypertension in adults is confirmed when a person has a clinic blood pressure of 140/90 mmHg or higher, alongside an ambulatory blood pressure monitoring (ABPM) daytime average or home blood pressure monitoring (HBPM) average of 135/85 mmHg or higher ¹.

The diagnostic process typically involves several steps:

• Initial Clinic Measurement: When considering a diagnosis, blood pressure should be measured in both arms ¹. If the clinic blood pressure is 140/90 mmHg or higher, a second measurement should be taken during the same consultation ¹. If the second measurement is substantially different from the first, a third measurement should be taken, and the lower of the last two measurements recorded as the clinic blood pressure ¹.
• Confirmatory Monitoring: If the clinic blood pressure is between 140/90 mmHg and 180/120 mmHg, ABPM should be offered to confirm the diagnosis ¹. If ABPM is unsuitable or the person is unable to tolerate it, HBPM should be offered instead ¹.
• ABPM Protocol: For ABPM, at least two measurements per hour should be taken during the person's usual waking hours (for example, between 08:00 and 22:00) ¹. The average value of at least 14 measurements taken during waking hours is used to confirm the diagnosis ¹.
• HBPM Protocol: For HBPM, two consecutive measurements should be taken at least one minute apart with the person seated for each recording ¹. Blood pressure should be recorded twice daily, ideally in the morning and evening, for at least four days, and ideally for seven days ¹. Measurements from the first day should be discarded, and the average of all remaining measurements used for diagnosis ¹.
• Further Actions: While waiting for diagnosis confirmation, investigations for target organ damage and a formal assessment of cardiovascular risk should be carried out ¹. If hypertension is not diagnosed, clinic blood pressure should be measured at least every five years subsequently, and considered more frequently if the person's clinic blood pressure is close to 140/90 mmHg ¹.