04 January 2007
All people with diabetes have to work to keep the amount of glucose in their blood as near to ideal as possible. This is called being in control. You want diabetes control because you will feel better.
Also, keeping blood glucose levels near the normal range can help prevent or delay the start of such diabetes side effects as nerve, eye, kidney, and blood vessel damage.
When you learned you had diabetes, you and your health-care team worked out a diabetes care plan. The plan aims to balance the foods you eat with your exercise and, possibly, blood glucose-lowering pills or insulin. You can do two types of tests to help keep track of how your plan is working. These are blood glucose tests and urine tests.
Blood Glucose Tests
Blood testing is the main tool you have to check your diabetes control. This test tells you your blood glucose level at any one time. Keeping a log of your test results is vital. When you bring this record to your doctor's office, you have a good picture of your body's response to your diabetes care plan.
Blood testing lets you see what works and what doesn't. This allows you and your doctor, dietitian, or nurse educator to make needed changes.
Who Should Test?
Experts feel that blood testing may help anyone with diabetes, even those not taking insulin. The American Diabetes Association recommends blood glucose testing if you have diabetes and are:
On intensive insulin therapy.
Having a hard time controlling your blood glucose levels.
Having severe low blood glucose levels or ketones from high blood glucose levels.
Having low blood glucose levels without the usual warning signs.
Urine tests for glucose are not as accurate as blood tests. This is because urine glucose shows what glucose levels were in the past few hours. Because blood tests tell you current blood glucose level, urine testing for glucose should not be done unless blood testing is impossible.
A urine test for ketones is another matter. This is an easy test that is very important when your diabetes is out of control or when you are sick.
You can find moderate or large amounts of ketones in urine when your body is burning fat instead of glucose for fuel. This happens when there is too little insulin at work. Everyone with diabetes needs to know how to test their urine for ketones.
How Blood Tests Work
There are two ways to test your blood. In both, you first prick your finger with a special needle, called a lancet, to get a drop of blood. Prick the side of your finger by your fingernail to avoid having sore spots on the parts of your finger you use the most.
What you do next depends on the type of blood glucose tests you use. For one method, you match a test strip to a color chart. For the other, you use a blood glucose meter to 'read' your blood glucose level. Be sure that your doctor or nurse educator shows you the correct way to test.
Testing With Strips for Visual Reading
For this type of test, you:
Place a drop of blood on a test strip (a piece of paper or plastic with a chemically treated pad).
Wait for the pad to change colour (glucose causes the change). Each brand of strip needs a certain time for the pad to develop.
Match the colour of the pad to a colour chart on the test strip bottle.
The colours on the chart stand for ranges of glucose levels, for example, 3 and 5 mmol/L. If your test strip colour matches 3, then your blood glucose is 3 mmol/ l. If it falls between 3 and 5, you record it as 4.
If you have poor eyesight or are colour blind, this type of blood glucose test will not work for you.
Testing With a Blood Glucose Meter
Blood glucose meters are small computerized machines that 'read' your test strip pad. For some meters, you put a drop of blood on a test strip pad, wait for the pad to develop, wipe off the blood, and then place the strip in the meter. For others, you put a drop of blood in the meter itself and then wait.
In both types of meter, your blood glucose level shows up as a number on a screen (like that on your pocket calculator). Reading a visual colour-matched strip gives a blood glucose range.
Picking a Meter
There are many meters to choose from. Some meters are made for those with poor eyesight. Others come with memory so you can store your test results in the meter itself. The Persatuan Diabetes Malaysia does not endorse any products or recommend one meter over another. PDM stocks a wide range of meters at the secretariat where patients can buy them at much reduced prices. If you plan to buy a meter, here are some questions to think about:
What meter does your doctor or diabetes educator suggest? They may have meters that they use often and know best.
What will it cost? Don't assume that your health insurance will cover the cost of a meter. Also consider the cost of testing supplies, such as test strips, when you think about which meter to buy. Once you choose a meter, you'll also have to buy the matching test strips. Shop around. Rebates are often offered.
How easy is the meter to use? Methods vary. Some have fewer steps than others.
How simple is the meter to maintain? Is it easy to clean? How is the meter calibrated (set correctly for the batch of test strips you are using)?
Are Meters Accurate?
Experts testing meters in the lab setting found them accurate and precise. That's the good news. The bad: meter mistakes most often come from the person doing the test. For good results you need to do each step correctly. But there is an easy way to check your skill.
Bring your meter to your doctor's office. Do a blood test within 5 or 10 minutes of when you've had blood drawn from your vein. Compare your test results with the doctor's blood test. Your meter results should not be off by more than 10 or 15 percent.
Here are other things that can cause your meter to give a poor reading:
A dirty meter.
A meter that's not at room temperature.
An outdated test strip.
A meter not calibrated (set up for) the current box of test strips.
Ask your health-care team to check your testing skills every once in a while. Error can creep in over time.
Logging Your Results
When you finish testing, write down your results. There is more to testing than finding out a number. That's why keeping a log of your test results and related events (like exercise, unusual excitement, and special meals) is so important. You and your doctor or diabetes educator can use your records to learn what your test results mean for you. This takes time.
Ask your doctor or nurse if you should report test results out of a certain range at once by phone.
Keep in mind that test results often trigger strong feelings. Test numbers can leave you upset, confused, frustrated, angry, or down. It's easy to use the numbers to judge yourself. Remind yourself that your blood glucose level is a way to track how well your diabetes care plan is working. It is not a judgment of you as a person.
Testing for Ketones
You may need to test your urine for ketones once in a while. Ketones build up in your blood and then 'spill' over into your urine. It is much more common for ketones to build up if you have type 1 (insulin-dependent) diabetes than type 2 (non-insulin-dependent) diabetes.
Urine tests are simple, but to get good results, you have to follow directions carefully. Check to be sure that the test strip is not outdated. Read the insert that comes with your test strips. Go over the correct way to test with your doctor or nurse.
Here's How Most Urine Tests Go:
Get a sample of your urine in a clean container.
Place the test strip in the sample (you can also pass the strip through the urine stream).
Gently shake excess urine off the strip.
Wait for the test strip pad to change colour. The directions will tell you how long to wait.
Compare the strip pad to the colour chart on the test strip bottle. This gives you a range of the amount of ketones in your urine.
Record your results.
What do your test results mean? Small or trace amounts of ketones may mean that ketone buildup is starting. You should test again in a few hours. Moderate or large amounts are a danger sign. They upset the chemical balance of your blood and can poison the body.
Never exercise when your urine tests show moderate or large amounts of ketones and your blood glucose is high. These are signs that your diabetes is out of control. Talk to your doctor at once if your urine tests show moderate or large amounts of ketones.
Keeping track of your test results and related events is important. Your log gives you the data you and your doctor and diabetes educator need to adjust your diabetes care plan.
When to Test
Ask your doctor or nurse when you should test for ketones. You may be advised to test for ketones when your blood glucose is more than 13.3 mmol/L and you have type 1 diabetes.
Other good times to check for ketones are when:
You are sick (for example, with a cold or flu).
You feel tired all the time.
You are thirsty or have a very dry mouth.
Your skin is flushed.
You have a hard time breathing.
Your breath smells 'fruity'.
You feel confused or 'in a fog.'
These can be signs of high ketone levels that need your doctor's help.