Accurate or Not? At-Home Cholesterol Tests and Blood Pressure Monitors

The advantages and disadvantages of checking your cholesterol and blood pressure at home.

From the WebMD Archives

If you have high cholesterol or high blood pressure (or if you're worried about having it), you may have been tempted by the many at-home cholesterol tests and blood pressure monitors currently on the market. The devices promise quick, accurate results in the privacy of your own home, a boon for busy people who don't like to sit in waiting rooms. But do they actually work? And are they worth the investment? Read on to learn which products are worth the money and which are not.

Home Cholesterol Tests

Approved by the FDA in 1993, home cholesterol tests generally measure the total fat levels in your blood. A few years ago, some manufacturers also started producing home cholesterol tests that measure high-density lipoprotein (HDL), the "good" cholesterol that protects your heart; low-density lipoprotein (LDL), the "bad" cholesterol which contributes to plaque buildup in the arteries; and triglycerides.

To use the cholesterol tests, you prick your finger with a small lancet, put a drop of blood on a piece of paper with chemicals on it, and wait for the results (usually within 10 minutes or so). In some tests, you can tell your results by the color of the paper. In others, your result appears on a small screen -- often within one minute.

The results of home cholesterol tests are about 95% accurate -- very close to the accuracy of a doctor's (or laboratory's) test.

Home cholesterol tests cost between $14 (for the kind that uses paper strips) and $125 (for a hand-held automatic cholesterol device that tests total cholesterol, LDL, HDL, and triglycerides). That may sound like a pretty good deal, as even the higher-end devices would save you trips to -- and waiting time at -- the doctor's office or medical laboratory. But the home cholesterol tests have a number of problems that may not make them a good investment.

First, the most readily available (and affordable) tests only measure total cholesterol. A full understanding of your cholesterol profile requires measurements of HDL, LDL, and triglycerides as well.

Second, even if you get a sophisticated cholesterol test, a doctor needs to review your results in combination with your other risk factors -- such as family history, nutritional habits, age, and gender -- to really understand your risk for cardiovascular disease.

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Third, and perhaps most important, blood cholesterol -- unlike blood pressure -- doesn't change on a day-to-day or even week-to-week basis. Doctors recommend that healthy adults get cholesterol tests every five years; people with higher cholesterol levels or risk factors for cardiovascular disease may need to be tested more often. But even then, testing at home isn't really necessary.

Bottom line: At-home cholesterol tests may satisfy your curiosity, but they don't provide enough information to be truly helpful.

Home Blood Pressure Monitors

Home blood pressure monitors are a different story. They allow you to measure your blood pressure on a daily or even hourly basis, so you can gauge the effect of medication, activities, time of day, or even emotions on your blood pressure. They can be crucial if you tend toward high blood pressure, or if you have normal blood pressure, but get high readings at the doctor's office, a condition called "white coat hypertension."

Like blood pressure monitors in a doctor's office, the at-home monitors measure the force of blood inside an artery in your arm. During the test, a cuff that is wrapped around your arm inflates, temporarily stopping the flow of blood in your arm. When the cuff is released, you (or the nurse or the device) will listen for the sound of blood flowing back into the artery.

You can choose from three different types of blood pressure monitors.

Manual Blood Pressure Monitors

Technically called "sphygmomanometers," manual blood pressure monitors consist of an arm cuff, a squeeze bulb, a gauge (or digital display), and a stethoscope or microphone. To use them, you strap the cuff onto your arm, squeeze the bulb, and listen for the sound of your pulse starting and then fading away again.

Manual blood pressure monitors cost between $20 and $30 and can be difficult to use, especially if you're not used to using a stethoscope, if you have impaired vision or hearing, or if you have trouble with manual dexterity.

Automatic (or Digital) Blood Pressure Monitors

Powered by batteries, automatic blood pressure monitors have a cuff that is attached to your wrist or upper arm. An electronic monitor inflates and deflates the cuff, making this kind of device far easier to use than the manual ones. The monitor then displays your blood pressure. These blood pressure monitors generally cost between $40 and $100. Although they're easier to use, they're also sensitive and the readings can be influenced by your body position. Health professionals generally recommend having these devices adjusted at least once a year to make sure they're still accurate.

Despite the problems with both kinds of blood pressure monitors, many doctors encourage their patients to use them, so that they can be aware of dangerous spikes in their blood pressure and take a more active role in their home care. But if you do decide to monitor your own blood pressure, remember:

  • To avoid fraud, buy monitors only from reputable pharmacies or medical supply stores and be sure they are FDA approved.
  • Follow the manufacturer's directions to make sure you're getting the most accurate readings.
  • Share the results with your doctor, so that he or she can advise you on the next step.
WebMD Feature Reviewed by Charlotte E. Grayson Mathis, MD on January 08, 2007

Sources

SOURCES: Roger Blumenthal, director, Ciccarone Preventive Cardiology Center, Johns Hopkins University. Amit Khera, MD, assistant professor of medicine, University of Texas, Southwestern Medical School. American Academy of Family Physicians web site: "Blood Pressure Monitoring at Home." FDA web site: "Home Diagnostic Tests: The Ultimate House Call?"

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