High Blood Pressure Diagnosis

A single high blood pressure reading does not necessarily mean that a person has high blood pressure (hypertension). People are diagnosed with high blood pressure when their blood pressure continues to stay high over time.

According to the American Heart Association, blood pressure readings are interpreted as follows:

Both the systolic and diastolic readings are important. If the readings fall into different stages listed in the chart, a person's blood pressure is interpreted using the lower (higher risk) blood pressure stage.

People with prehypertension are more likely to develop high blood pressure. Fortunately, they may be able to lower their blood pressure by making lifestyle changes. If their blood pressure continues to rise, they may also be prescribed medications.

Low blood pressure

Although blood pressure below 120/80 is highly desirable, it's possible for a person's blood pressure to get too low (hypotension). Low blood pressure is defined as a blood pressure lower than 90/60 or a sudden drop of 20 mm Hg. People with low blood pressure may experience symptoms, such as confusion, dizziness, and fainting. Low blood pressure may be caused by advanced diabetes, an allergic reaction, blood loss, dehydration, heart problems, and some medications.

Blood pressure measuring devices

Several instruments are used to measure blood pressure. The most common approach uses a stethoscope and a sphygmomanometer. The stethoscope is used to listen to sounds produced in the body, in this case the sound of blood flowing through an artery. The sphygmomanometer is used to measure blood pressure in the arteries.

When measuring blood pressure, people should be seated with an arm resting on a table. The arm should be bare and be positioned at heart level. The healthcare worker tightens the cuff of the sphygmomanometer around the person's upper arm and places the head of the stethoscope inside the person's elbow joint. The healthcare worker then listens through the earpieces of the stethoscope while releasing the cuff pressure. The first audible sound heard is the systolic blood pressure (in the brachial artery) and the last audible sound heard is the diastolic blood pressure.

As automatic digital blood pressure monitors become less expensive and more reliable, they are starting to replace the manual models.

Tests

Once high blood pressure is diagnosed, a doctor may perform additional tests for high blood pressure complications that affect the blood vessels, heart, kidneys, and eyes. The tests may include:

• Chem-20
  Chem-20 is a group of chemical blood tests. The test measures a person's total cholesterol, total protein, electrolytes (such as, sodium, potassium, chlorine), and liver and kidney chemicals. The test helps diagnose such conditions as high cholesterol and kidney disease.
• Echocardiography
  Echocardiography uses ultrasound waves to produce an image of the heart muscle. The procedure is used to diagnose heart and cardiovascular diseases.
• Electrocardiography
  Electrocardiography (ECG, EKG) measures electrical activity in the heart and is used to diagnose heart problems.
• Urinalysis
  A urinalysis is a series of physical, chemical, and microscopic tests of a urine sample that help test for conditions, such as diabetes, kidney disease, and malignant hypertension.
• X-rays of the kidneys
  X-rays of the kidneys help diagnose kidney disorders. High blood pressure is a leading cause of kidney failure. When the blood vessels become damaged due to uncontrolled high blood pressure, extra fluid builds up in the body, which raises a person's blood pressure even higher.
• Eye exam
  An eye exam can test for hypertensive retinopathy, which is damage to the retina due to uncontrolled high blood pressure. The retina is the light-sensitive membrane lining the back of the eyeball.

Measuring blood pressure at home

People can measure their blood pressure at home to check that their blood pressure medication is working and warn them if their blood pressure is getting too high. Home blood pressure devices are also helpful for people with "white coat" hypertension.

People should discuss their choice of home blood pressure monitor with a healthcare worker and may need training to learn how to use the blood pressure device correctly. It's also advisable to bring the home monitor to doctor visits to verify that it is being used properly and determine if it needs to be calibrated.

Manual monitors

Digital monitors

Cuffs are available for the upper arm, wrist or finger. Arm cuffs are the most accurate and finger cuffs are the least accurate. Small and large people may require special-sized cuffs. Extra features, such as a paper printout and error checking are available in the more expensive models.