The biggest advancement in diabetes control has been the development of blood glucose monitors. A blood glucose monitor (GM) is a small, portable device that can be used by a person who has diabetes to measure the level of glucose in their own blood. These instruments allow people to measure changes which occur in their blood glucose levels on a regular basis.

How does a glucose monitor work?

Blood glucose levels can be measured using a drop of blood from a finger tip and applying it to a reagent strip. The blood on the test strip reacts with the materials on the test area causing a colour change or an electric current in proportion to the amount of glucose in the blood. The electrical components of the GM use the colour change or electric current to identify the amount of glucose present in the blood sample. This result is displayed on the GM screen.

There are many different GMs now available in Canada with more to come, including a “talking” GM for the visually impaired or blind. Modern technology is constantly making the GMs more reliable, smaller, faster and easier to use. Research is progressing on non-invasive GMs that will not require a blood sample, but these products are still five to 10 years away.

Why is testing needed?

Diabetics should test their blood glucose levels regularly to determine if they need insulin or medication adjustments. This regular testing helps avoid emergency situations, such as hypoglycemia (low blood sugar) or hyperglycemia (high blood sugar). Testing is especially important for anyone who does not feel the onset of a hypoglycemic episode, particularly those who live alone. Monitoring blood glucose levels motivates people with diabetes to manage their diabetes more effectively and, therefore, improve the quality of life and reduce serious long-term consequences of diabetes.

Glucose monitoring is strongly recommended for:

anyone using insulin for either Type I or Type II diabetes;
pregnant women with pre-existing diabetes or gestational diabetes;
most patients with Type II diabetes treated with oral medications;
anyone who is at risk for hypoglycemia especially if they have little or no symptoms of hypoglycemia; and
most patients with diabetes being treated by diet alone.

Features to Consider When Buying a Glucose Monitor

If you are diabetic and thinking of buying a glucose monitor, keep the following points in mind:

Accuracy and Precision
All the GMs on the market are fairly accurate (within 15 per cent of clinical laboratory measurements) when used according to manufacturer’s instructions. It is important to conduct regular quality control tests on your GM by using the control solution provided by the manufacturer and by checking the GM with the calibration strip.

Maintaining the precision of the GM is equally important. Precision refers to the similarity or 'closeness' of the test results using the same blood sample for a series (for instance, 20) of tests with the same GM. Most GM strips have been improved to produce more lab-like results.

Cost
The price of a GM has dropped in the last few years. Also, most manufacturers have trade-in or rebate offers to allow you to purchase a newer GM. However, the cost of the test strips remains relatively high and is still one of the biggest problems with the use of a GM. Some insurance companies cover a percentage of the cost of the GM and strips. Check with your insurance company and find out what is covered for a person with diabetes. Some provincial governments have programs that cover a percentage of the cost of supplies. Ask your pharmacy to keep you informed about sales, rebates and trade-in offers. Also, ask your pharmacist for information on financial assistance for your diabetes supplies.

Ease of Use
Most of the new models of GM are very user-friendly. They require fewer steps to use them and they have larger visual displays. Some even have instructions on how to operate the GM shown on the display. Older models of GM needed special cleaning but this is not necessary with most new models.

Size of the Drop of Blood
Most of the new models require a smaller drop of blood than the older models.

Warranty
Be sure the GM you buy has a warranty and do not forget to fill in the warranty card and mail it to the manufacturer. Most GMs have four-year warranties and some even have lifetime warranties. All the manufacturers have excellent customer service departments. If there is something wrong with your GM, they will replace it.

Size and Portability of the GM
Most of the newer models are smaller and have more compact cases, making it easier to carry the GM with you at all time. However, it is important to note that the GM should be protected against extreme temperatures during transport.

Special Features
Memory: Most GMs can store from one to 250 test results in their memories. The GM memory, however, should not be used to replace your diabetes log book.
Computer Program: Some GMs have computer programs that can show statistics to make the test results more meaningful.
Voice Synthesizer: Voice synthesizers that gives auditory instructions for the visually impaired or blind person.

Accessories
GMs may come with various accessories such as strips, lancets, a finger lancing device and quality control solutions. Sometimes these accessories need to be purchased separately. Find out what is included with each type of kit and what needs to be purchased in addition for the proper use of the GM.

Performing a Blood Glucose Test With Your GM

Wash your hands with warm, soapy water and dry them thoroughly.
Prepare your blood letting device with a sterile lancet (the needle that pricks your finger). A finger-letting device should be used to limit the depth of skin penetration of the lancet.
Place hands together palm to palm, finger to finger. All the places you can see on both sides of the fingers can be used for obtaining a drop of blood. Fingers should be used in rotation. Never use an infected or injured finger to obtain a drop of blood.
Gently message the hand from wrist to the finger with the puncture site to ensure that a hanging drop of blood is produced.
Apply the drop of blood to the reagent strip and make sure the test area on the strip is covered completely.
Use a clean tissue to remove excess blood from the finger.
Record the test result in your diabetes log book. Be honest about your results. Take your log book to your next appointment with your doctor and diabetes educator.
Teach family members how to use your GM and how to recognize and treat a hypoglycemic reaction.

What To Do If Your Glucose Monitor Is Not Working Properly

Check your GM. Ensure that it is clean, especially the test area.
Check the expiry date on the test strips. Check the strips for damage or color changes when you first open a bottle of strips. Write the date the bottle was opened on the side of the bottle.
Check your GM with the calibration strip and the glucose control solution according to the manufacturer’s instructions.
Check the batteries to ensure they have enough power to allow the GM to operate properly.
Check the procedures used for conducting the test. Is the GM being used correctly?
Check the GM results against the results of a blood glucose test conducted by a clinical laboratory. Perform a test using a drop of blood from your finger within five minutes after a blood sample is taken from your arm at the clinical laboratory. The result given by the GM should be within 15 per cent of the result produced by the clinical laboratory. Whole blood (from your finger) produces test results that tend to be 10 to 12 per cent lower than the clinical laboratory results that are conducted with blood plasma. Some monitors are now adjusted to read a result closer to the clinical laboratory’s result.
If the GM is not working properly, call the service department of the manufacturer. The toll-free number is printed in the instruction manual for the GM.

Patient Guidelines for Infection Control

As with any procedure where the skin is punctured, there is always the need to prevent infection.

Wash hands with soap and water before testing.
Do not share the lancet used for doing the finger prick.
Wash the finger letting device regularly.
Use a sterile lancet each time you test.
Keep the test area and the GM clean.
Do not test another person’s blood on the GM.
Dispose of your lancets, used strips and tissues properly. This means using a hard container with a screw-on lid. When the container is full, take it to your pharmacy for proper disposal.

How Often Should You Check and What is the Proper Blood Glucose Level for You?

See your doctor and diabetes educator. They will work out a treatment plan for managing your diabetes according to your age and type of diabetes. They will also set a target range for your blood glucose levels and work out a testing schedule.

Remember, keeping your blood glucose levels as close to normal as possible will help prevent or delay the serious complications of diabetes. It is recommended that blood glucose levels be tested more frequently during:

illness
times of adjustments in medication or insulin
low blood glucose (hypoglycemic reactions)
changes in diet or intake of food
pregnancy
stressful situations
vigorous exercise
persistent high blood glucose levels

Obtaining the Proper Instructions and GM Support Services

It is important to buy your GM at a pharmacy with a diabetes center that can provide the necessary support for both you and the instrument. Proper instructions for the operation of a GM should be provided by a qualified person. Look for a pharmacy that provides a teaching area away from distractions and noise. Ask about the different types of GMs and discuss their operation as it applies to your individual needs. Choose a GM that fits your lifestyle and addresses your concerns. For instance, if you have a problem with vision, look for a GM with a large display.

Develop a good relationship with your pharmacy in order to keep up-to-date on new products, sales, trade-in and rebate offers. The pharmacy may also provide you with pamphlets and videos from the resource centre. The pharmacy will also have the computer programs available to provide print outs of your GM test results.

It is very important to talk to your pharmacist about over-the-counter drugs and prescriptions that might affect your blood glucose levels. Many prescription medications may raise blood glucose levels or lower them and can do so in varying degrees in different people. Most can still be used by diabetics but the patients should be aware of the possible effect the drugs may have on their glucose levels and report any noticeable changes to their doctors.

It is important to try to fill your prescriptions at the same pharmacy each time so the pharmacist has an accurate record of all of the medications you are currently using and can warn you of any potential problems.

There are also a number of non-prescription medications that may alter blood glucose levels.

Prescription Medications That May Raise Blood Glucose Levels

Acetazolamide (e.g. Diamox™)
Benzodiazepines (e.g. Valium™)
Beta Blockers (e.g. Inderal™)
Calcium Channel Blockers (e.g. Cardizem™)
Corticosteroids ( e.g. Deltasone™)
Cyclophosphamide (e.g. Procytox™)
Diuretics (e.g. Dyazide™, Lasix™)
Estrogens (e.g. Premarin™)
Glucagon
Lithium (e.g. Carbolith™)
Nicotine patches, gum (e.g. Nicoderm™, Nicorettes™)
Non-steroidal anti-inflammatories (e.g. Motrin™)
Oral Contraceptives (e.g. Triphasil™)
Phenytoin (e.g. Dilantin™)
Thyroid replacements ( e.g. Synthroid™)
Prescription Medications That May Lower Blood Glucose Levels
Allopurinol (e.g. Zyloprim™)
Beta Blockers (e.g. Inderal™)
Chloroquine (e.g. Aralen™)
Cimetidine (e.g. Tagamet™)
Clofibrate (e.g. Atromid-S™)
Clonidine (e.g. Catapres™)
Disopyramide (Rythmodan™)
MAO Inhibitors (e.g. Parnate™)
Potassium salts (e.g. Slow-K™)
Probenecid (e.g. Benemid™)
Reserpine (e.g. Serpasil™)
Sulfonamides (e.g. Septra™)

Non-prescription medications or ingredients that raise or lower glucose levels.

Alcohol
Caffeine
Decongestants (e.g. pseudoephedrine, phenylpropanolamine)
Lozenges
Niacin, Nicotinic Acid (high doses)
Nicotine gum
Salicylates (high doses)

Always check with your pharmacist before buying over-the-counter medications if you are unsure about the effect on your glucose levels. For instance, a number of cold or flu remedies contain decongestants that may lead to hyperglycemia (high blood glucose levels). Read the labels carefully and take the product only as directed on the package.

Your pharmacist is always willing and able to give advice and help you find a product best suited to your needs.

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