How Is  High Blood Pressure Diagnosed?

Your doctor will diagnose  high blood pressure (HBP) using the results of blood pressure tests. These tests will be done several times to make sure the results are correct. If your numbers are high, your doctor may have you return for more tests to check  your blood pressure over time. 

If your blood pressure is 140/90 mmHg or higher over time, your doctor  will likely diagnose you  with HBP. If you have diabetes  or chronic kidney disease, a  blood pressure of 130/80 mmHg or higher is considered HBP. 

The HBP ranges in children are different. 

How Is Blood Pressure Tested? 

A  blood pressure test is easy and painless. This test is done at a doctor's office or clinic. 

To prepare  for the test: 

• Don't drink coffee or smoke cigarettes for 30 minutes prior to the test. These actions may cause a short-term rise in your blood pressure. 
• Go to the bathroom before the test. Having a full bladder can change your  blood pressure reading. 
• Sit for 5 minutes before  the test. Movement can cause short-term rises in blood pressure. 
• To measure  your blood pressure, your  doctor or nurse will use some type of a gauge, a stethoscope (or electronic sensor), and a blood pressure cuff. 

Most often,  you will sit or lie down with the cuff around  your arm as your doctor or nurse checks your blood pressure. If he or she doesn't tell you what your blood pressure numbers are, you should ask. 

Diagnosing High Blood Pressure in Children and Teens 

Doctors measure blood pressure in children and teens the same way they do in adults. Your child should have routine  blood pressure checks starting  at 3 years of age. 

Blood pressure normally rises with age and body size. Newborn babies often have very low blood pressure numbers, while older teens have numbers similar  to adults. 

The ranges for normal blood pressure and HBP are generally lower for youth than for adults. These ranges are based on the average blood pressure numbers for age, gender, and height. 

To find out whether  a child has HBP, a doctor will compare the child's  blood pressure numbers to average numbers  for his or her age, height,  and gender. 

For more information, see the National Heart, Lung, and Blood Institute's "A Pocket Guide to Blood Pressure Measurement in Children." 

What Does a Diagnosis of High Blood Pressure Mean? 

If you're diagnosed with HBP, you will need treatment. You also will need to have your  blood pressure tested again to see how treatment affects it. 

Once your blood pressure is under control,  you will need to stay on treatment. "Under control" means that your  blood pressure numbers are normal. You also will need regular blood pressure tests. Your doctor can tell you how often you should be tested. 

The sooner you find out about HBP and treat it, the better your chances to avoid problems like heart attack, stroke, and kidney failure.