There is no current standard UK definition of hypertension in children. However, the issue has been researched in some detail in the USA, where a working group in 2004 defined the condition as an average systolic and/or diastolic blood pressure ≥95th percentile for gender, age and height on three or more separate occasions.2
This is a companion discussion topic for the original article at https://patient.info/doctor/paediatrics/hypertension-in-childhood