Tests for High Blood Pressure

Medically Reviewed by Brunilda Nazario, MD on September 20, 2021
3 min read

High blood pressure usually has no symptoms. The only sure way to tell that you have it is to measure it with a device called a sphygmomanometer. It has a gauge and a rubber cuff that's placed around your arm or leg and inflated.

The person taking your blood pressure wraps the cuff around your upper arm. Some cuffs go around the forearm or wrist, but often, they're not as accurate.

Your doctor or nurse will use a stethoscope to listen for the appearance and disappearance of sound produced by the pulse in your elbow region. That's how the systolic and diastolic blood pressures are determined.

They’ll inflate the cuff to a pressure higher than your systolic blood pressure, and it will tighten around your arm. Then, they'll release it. As the cuff deflates, the first sound they hear through the stethoscope is the systolic blood pressure. It sounds like a whooshing noise. The point where this noise goes away marks the diastolic blood pressure.

In a blood pressure reading, the systolic number always comes first, and then the diastolic number.

Having your blood pressure measured is painless and takes just a few minutes.

Blood pressure (BP) is classified as follows by the American Heart Association:

  • Normal BP:  Systolic less than 120 mmHg; diastolic less than 80
  • Elevated BP: Systolic is between 120 and 129 mmHg; diastolic less than 80
  • Stage 1 High BP: Systolic is 130–139 mmHg or your diastolic is between 80-89
  • Stage 2 High BP: 140 or greater systolic, or 90 or greater diastolic

Tests may be ordered by your health care provider to check for causes of high blood pressure and to assess any organ damage from high blood pressure or its treatment. These tests may include the following:

  • Blood tests, including measurement of electrolytes, blood urea nitrogen, and creatinine levels (to assess kidney involvement)
  • Lipid profile for levels of various kinds of cholesterol
  • Special tests for hormones of the adrenal gland or thyroid gland
  • Urine tests for electrolytes and hormones
  • A noninvasive, painless eye examination with an ophthalmoscope will look for ocular damage
  • Ultrasound of the kidneys, CT scan of the abdomen, or both, to assess damage or enlargement of the kidneys and adrenal glands

Any of the following may be performed to detect damage to the heart or blood vessels:

  • Electrocardiogram (ECG) is a noninvasive test that detects the electrical activity of the heart and records it on paper. ECG is helpful for evaluating for damage of the heart muscle, such as heart attack, and/or thickening/hypertrophy of the heart wall/muscle, common complications of high blood pressure
  • Echocardiogram is an ultrasound examination of the heart taken through the chest. Sound waves take a picture of the heart as it beats and relaxes and then transmits these images to a video monitor. The echocardiogram can detect problems with the heart such as enlargement, abnormalities in motion of the heart wall, blood clots, and heart valve abnormalities. It also gives a good measurement of the strength of the heart muscle (ejection fraction). The echocardiogram is more comprehensive than an ECG, but also more expensive.
  • A plain chest X-ray primarily provides an estimate of the size of the heart, but it is much less specific than echocardiography, which provides more detail.
  • Doppler ultrasound is used to check blood flow through arteries at pulse points in your arms, legs, hands, and feet. This is an accurate way to detect peripheral vascular disease, a common finding in people with high blood pressure. It also can depict the arteries to both kidneys and sometimes depicts narrowings that can lead to high BP in a minority of patients.