Diagnosis and classification criteria for hypertension

Hypertension is diagnosed and graded according to criteria that are performed when the patient is not taking antihypertensive drugs. Clinically, hypertension is divided into three grades. Grade 1 is also mild hypertension. Systolic blood pressure is between 140 and 159 mm Hg, diastolic blood pressure is between 90 and 99 mm Hg. Grade 2 hypertension is moderate hypertension, usually increasing by 20 mm Hg on the basis of Grade 1. Grade III hypertension is also severe hypertension, systolic blood pressure is higher than 180 mm Hg, diastolic blood pressure is higher than 110 mm Hg.