trouble shooting your glucose meter

Featuring Grace C. Eaton, LPN

When people with diabetes can control their blood sugar (glucose), they are more likely to stay healthy. People with diabetes can use a number of tools to help them better manage their diabetes.  One of these tools is a home glucose meter.

Glucose meters help people with diabetes check their blood sugar at home, school, work, and play. Other blood and urine tests reveal trends in diabetes management and help identify diabetes complications.  We are going to discuss the glucose meter (glucometer) and how it can help you control your diabetes.

Self-Monitoring of Blood Glucose

The process of monitoring one’s own blood glucose with a glucose meter is often referred to as self-monitoring of blood glucose or “SMBG.”
To test for glucose with a typical glucose meter, place a small sample of blood on a disposable “test strip” and place the strip in the meter. The test strips are coated with chemicals that combine with glucose in the blood.

The meter measures how much glucose is present. Meters do this in different ways. Some measure the amount of electricity that can pass through the sample. Others measure how much light reflects from it. The meter displays the glucose level as a number. Several new models can record and store a number of test results. Some models can connect to personal computers to store test results or print them out.

Choosing a Glucose Meter

At least 25 different meters are commercially available.  They differ in several ways including:

  • Amount of blood needed for each test
  • Alternate testing sites (for example, using the forearm instead of a finger)
  • Testing speed
  • Overall meter size
  • Ability to store test results in memory
  • Cost of the meter
  • Cost of the test strips used  (Insurance companies will often cover the cost of testing strips for certain meters….contact your insurance for the best coverage.)

Newer meters often have features that make them easier to use than older models. Some meters allow you to get blood from places other than your fingertip (Alternative Site Testing). Some new models have automatic timing, error codes, and signals, or barcode readers to help with calibration. Some meters have a large display screen or spoken instructions for people with visual impairments.

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Using Your Glucose Meter

Diabetes care should be designed for each individual patient. Some patients may need to test (monitor) more often than others do. How often you use your glucose meter should be based on the recommendation of your health care provider. Self-monitoring of blood glucose (SMBG) is recommended for many people with diabetes, but especially for those who take insulin. The role of SMBG has not been defined for people with stable type 2 diabetes treated only with diet.
Often, self-monitoring plans direct you to test your blood sugar before meals, 2 hours after meals, at bedtime, and anytime you experience signs or symptoms. You should test more often when you change medications when you have unusual stress or illness, or in other unusual circumstances.

Please discuss your testing frequency with your personal provider or access the American Diabetes Association website at www.diabetes.org.

Learning to Use Your Glucose Meter

Not all glucose meters work the same way. Since you need to know how to use your glucose meter and interpret its results, you should get training from a diabetes educator. The educator should watch you test your glucose to make sure you can use your meter correctly. This training is better if it is part of an overall diabetes education program.

Instructions for Using Glucose Meters

The following are the general instructions for using a glucose meter:

  1. Wash hands with soap and warm water and dry completely or clean the area with alcohol and dry completely.
  2. Prick the fingertip (or alternative site if your meter allows that) with a lancet.
  3. Hold the hand down and hold the finger until a small drop of blood appears to catch the blood with the test strip.
  4. Follow the instructions for inserting the test strip and using the SMBG meter.
  5. Record the test result.

You should carefully read the instructions for both the meter and its test strips. Meter instructions are found in the user manual. Keep this manual to help you solve any problems that may arise. Many meters use “error codes” when there is a problem with the meter, the test strip, or the blood sample on the strip. You will need the manual to interpret these error codes and fix the problem.

You can get information about your meter and test strips from several different sources.

Your user manual should include a toll-free number in case you have questions or problems. If you have a problem and can’t get a response from this number, contact your health care provider or a local emergency room for advice. Also, the manufacturer of your meter should have a website. Check this website regularly to see if it lists any issues with the function of your meter.

Measurement Range

Most glucose meters are able to read glucose levels over a broad range of values from as low as 0 to as high as 600 mg/dL. Since the range is different among meters, interpret very high or low values carefully.  Refer to the package insert of your glucose meter for the blood sugar range your meter will record.

Factors That Affect Glucose Meter Performance

The accuracy of your test results depends partly on the quality of your meter and test strips and your training. Other factors can also make a difference in the accuracy of your results. Some factors that can impact accuracy include the following:

  • Blood counts (hematocrit)
  • Vitamins and mineral supplements
  • Altitude, temperature, and humidity
  • Generic or third party test strips

Refer to the package insert of your meter for specific instructions regarding these factors.

Making Sure Your Meter Works Properly

You should perform quality-control checks to make sure that your home glucose testing is accurate and reliable. Several things can reduce the accuracy of your meter reading even if it appears to still work. For instance, the meter may have been dropped or its electrical components may have worn out. Humidity or heat may damage test strips. It is even possible that your testing technique may have changed slightly. Quality control checks should be done on a regular basis according to the meter manufacturer’s instructions. There are two kinds of quality control checks:

Check Using “Test Quality Control Solutions” or “Electronic Controls”
Test quality control solutions and electronic controls are both used to check the operation of your meter. Test quality control solutions check the accuracy of the meter and test strip. They may also give an indication of how well you use your system. Electronic controls only check that the meter is working properly.

Take Your Meter with You to The Health Care Provider’s Office.
This way you can test your glucose while your health care provider watches your technique to make sure you are using the meter correctly. Your health care provider will also take a sample of blood and evaluate it using a routine laboratory method. If values obtained on the glucose meter match the laboratory method, you and your health care provider will see that your meter is working well and that you are using a good technique. If results do not match the laboratory method results, then the results you get from your meter may be inaccurate and you should discuss the issue with your health care provider and contact the manufacturer if necessary.

New Technologies: Alternative Site Testing

Some glucose meters allow testing blood from alternative sites, such as the upper arm, forearm, base of the thumb, and thigh.  Sampling blood from alternative sites may be desirable, but it may have some limitations. Blood in the fingertips show changes in glucose levels more quickly than blood in other parts of the body. This means that alternative site test results may be different from fingertip test results not because of the meter’s ability to test accurately, but because the actual glucose concentration can be different. Glucose levels at the alternative site appear to change more slowly than in the fingertips.  Alternative site results may be different than the fingertip when glucose levels are changing rapidly (e.g. after a meal, taking insulin, or during or after exercise).

Do not test at an alternative site, but use samples taken from the fingertip, if …

  • you think your blood sugar is low,
  • you are not aware of symptoms when you become hypoglycemic, or
  • the site results do not agree with the way you feel.

Below are a few contact numbers for a few meters if you are having trouble with your meter, please use the toll-free number in your handbook or one of the ones below if you have one of these meters.

FREEDOM METERS
BAYER METERS
PRODIGY METERS
PRESTIQUE/TRU TRACK METERS
WAVESENSE
ONE-TOUCH METERS
ACCU-CHECK

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UPMC Harrisburg is a nationally recognized leader in providing high-quality, patient-centered health care services in south central PA. and surrounding rural communities. UPMC Harrisburg includes seven acute care hospitals and over 160 outpatient clinics and ancillary facilities serving Dauphin, Cumberland, Perry, York, Lancaster, Lebanon, Juniata, Franklin, Adams, and parts of Snyder counties. These locations care for more than 1.2 million area residents yearly, providing life-saving emergency care, essential primary care, and leading-edge diagnostic services. Its cardiovascular program is nationally recognized for its innovation and quality. It also leads the region with its cancer, neurology, transplant, obstetrics-gynecology, maternity care, and orthopaedic programs.

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