Glucose Monitor Accuracy, Why Home Monitors Are Not Perfect

Glucose monitor accuracy matters because you depend on your meter every day as a diabetic. How accurate is your glucose monitor? Here are some things you should know.

The international standards for diabetic meters allow for an up to 20% error rate. That is not comforting to know.

Glucose monitor accuracy is not something diabetics should have to worry about. If you take insulin you rely on the accuracy of your monitor.

You need an accurate blood sugar level before you take rapid acting insulin. There is no other way to know how much to inject.

But even type 2 diabetics who are not on insulin usually test once a day and whenever they feel the symptoms of a blood sugar low.

Monitor Accuracy Makes the News

The New York Times published an article on July 18, 2009. They reported that a 16-year-old girl bought seven meters and took them home to be tested by her diabetic dad as a science project.

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The results on the meters varied by up to 75 points. That disturbed the student's mother because she knew how her husband relied on his monitor's accuracy.

She worked for a senator and immediately told him about the experiment results. In turn, he wrote a letter to the FDA asking for an investigation.

The Response

The meter companies' response is that higher standards will make meters more expensive. They say they fear that people will not buy higher priced meters.

I remember that excuse. Car makers have always used it whenever they have been asked to make cars safer.

What meter companies should worry about is the lowered confidence their customers will have in their diabetic meters when the news spreads.

The companies that improve accuracy will be the smart ones. The newer meters are claiming to do this.

For example, AgaMatrix states that with their WaveSense they have concentrated on glucose monitor accuracy and addressed many of the problems other meters have.

After reading the ads, I bought a WaveSense meter on Amazon. But when I compared the readings to my Bayer Breeze, the numbers were no different. I am staying with the older Bayer Breeze because overall it is still better.

Problems with Glucose Monitors

One company was quoted to state that every meter has issues with medications. It all depends on the design used by each meter company.

Things like aspirin, Tylenol, vitamin C and dialysis medications can worsen glucose monitor accuracy.

There is more than one standard method to measure blood sugar. Keep in mind that the makers know their meter is allowed to be off by up to 20%.

It is the old argument of what is cost effective, which always ends in a cheap product.

The issue of glucose monitory accuracy and money exposes a serious problem. Many hospitals save money on blood glucose testing by using the cheaper home meters to check blood sugar in their patients.

FDA officials wrote that using home monitors may have led to deaths in some high risk cases. They stated that hospitals should not use home monitors because the accuracy standard is not good enough.

The variable quality of meters has been demonstrated in labs where dozens of glucose monitors get tested at once. One German test reported that only 60% of the 40 meters they tested had accuracy that met the 20% standard.

Faulty Readings Are Not Always the Meter's Fault

Beyond mistakes at the manufacturer there is another problem. Human error also lowers glucose monitor accuracy.

If you do not handle your monitor with care, or if you get in a hurry and skip steps you could get numbers that are way off.

If you have alcohol on your skin it affects your readings. It is better to wash your hands with soap and dry them well before you test. If you still use alcohol wipes, just be sure to let your skin dry before you prick your finger.

There are other problems too. Outdated or bent test strips are not accurate. Using the wrong strips for a meter will ruin the blood test. A meter that was exposed to high heat or humidity or allowed to get dirty will not work properly.

Getting Monitor Readings You Can Trust

What can you do? First, do some homework and find out which monitor is best for you. I love that monitors can be free, but some are truly better than others.

Several sites are available with side by side comparisons. On Amazon, every glucose meter has been rated by users. Read what they say, especially the bad reviews. It will help a lot.

While you are deciding which one to get, look at the price of the test strips because you will be buying them every month. A free monitor with high-priced test strips is not a bargain.

Take good care of your meter. Store it at room temperature, not in the refrigerator or near a heat source. Protect it from high heat, humidity and dust. All meters come with cases, so store yours inside one.

Next, if your meter has to be coded, check to make sure the number on the test strip vial matches the one on your display.

Always wash your hands before handling test strips. Make sure the strip is inserted all the way and the right way up in your meter. Glucose monitor accuracy is only as good as the test strip you are using.

Do not use outdated test strips or strips that have been exposed to high heat or humidity. Store them in the sealed container they came in.

Apply enough blood for the test. You cannot add more after the countdown starts. Do not use too much or the blood will get into your monitor and ruin it.

Your test site affects glucose monitoring accuracy. If you use an alternate site like your arm for the blood test, the number will be a little different from your fingerstick.

That is because the blood in your arm is slower to show blood sugar changes. So if you think your blood sugar is dropping but the arm test is not showing that, test again on your fingertip to be sure.

It is a good idea to have an extra battery on hand. Monitors tell you when the battery is dead, but there is no early warning that the battery is low.

If your meter is acting up, try changing the battery first before you toss out the monitor.

How to Keep Your Peace of Mind

If you are not confident about your glucose monitor accuracy, take the meter with you to the doctor's office and check a reading at the same time they take one so you can compare.

Your hemoglobin A1C numbers are the best way to know how your blood sugars have been doing over the past couple of months.

So when you compare your daily numbers to the A1C, that will prove your monitor is doing a pretty good job.

As long as you are aware that glucose monitor accuracy is not a precise numbers game, you will learn to trust your symptoms and reactions along with your meter readings.

They will help you decide whether you are having a hypoglycemic episode. Knowing the warning signs of a diabetic coma is more important now.

Be aware of how your body reacts to low blood sugar. This is crucial when you are taking insulin.

If you have diabetes or care for someone who is diabetic, a glucose monitor you can count on is not a luxury. It is a necessity.

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