1. Your blood pressure is 160/100 or higher.
2. Your blood pressure doesn't respond, or suddenly stops responding, to the usual medications.
3. You're younger than 30 or older than 55 and are suddenly diagnosed.
4. Your blood pressure is quite variable.
5. Your blood pressure is different in your right and left arms.
6. Your electrolyte (minerals like calcium, potassium, and sodium) levels are abnormal.
7. You have no family history of primary hypertension.
8. You're not obese.