Tests for High Blood Pressure

The only way to tell whether you have high blood pressure is to have it measured with a blood pressure cuff (sphygmomanometer).

• This device consists of a gauge and a rubber cuff that is placed around your arm and inflated.
  
  
• Having your blood pressure measured is painless and takes just a few minutes.

Blood pressure (BP) is classified as follows:

• Normal BP - Systolic less than 120 mm Hg; diastolic less than 80 mm Hg
  
  
• Prehypertension - Systolic 120-139 or diastolic 80-89 mm Hg

• High BP
  
  
  • Stage 1 - Systolic 140-159; diastolic 90-99 mm Hg
    
    
  • Stage 2 - Systolic more than 160; diastolic more than 100 mm Hg
    
    

Tests will be ordered 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, 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 may be done 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 quantitating any 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 echo 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 echo is more accurate 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 looks inside the heart.
  
  
• 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.