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Diabetes: Blood Sugar Self-Testing

Why is blood sugar testing important?

Testing your own blood sugar (glucose), also called self blood glucose monitoring, is an important part of managing diabetes. Testing your blood sugar regularly can:

  • Help you know if your blood sugar is within your target range. Staying in a healthy range can help prevent or delay long-term problems caused by high blood sugar, such as heart, kidney, eye, nerve, and circulation problems
  • Help you know if your blood sugar is too low or too high and treatment is needed
  • Help you know how much and which type of medicine to use, depending on your healthcare provider’s recommendations
  • Help you prevent low blood sugar during the night
  • Help you manage diabetes while you are sick
  • Let you know if you need to do a ketone test (if you have type 1 diabetes)
  • Help you learn the effects of certain foods, exercise, and stress on your blood sugar
  • Help your healthcare provider know if changes in your treatment are needed

What supplies are needed?

Doing a blood test requires:

  • Needle or lancet device: A small needle (called a lancet) is used to get a drop of blood for the test. Some lancet devices can be adjusted for different depths. This can be good for young children and for people with tender skin. Some lancet devices can also be adjusted so that you can use them to prick a finger, palm, arm, or other parts of your body. Be sure to use a new lancet each time. A sharp and clean lancet helps prevent injury and infection.
  • Blood glucose meter: There are many types of blood glucose meters and results from one meter may be different from another. It doesn’t matter which type of meter you choose, as long as you always use the same meter. Bring the meter to each clinic visit. Your healthcare provider can get a record of the test results from the meter.

    When looking for a blood glucose meter, make sure it:

    • Is accurate in the area where you live, for example, in cool or hot temperatures, high humidity, or high altitude
    • Can store at least the last 100 test values (to share with your healthcare provider at your checkups)
    • Is small enough to carry with you, such as in your handbag or backpack
    • Is easy to keep clean and care for

Your provider, nurse, or diabetes educator will show you how to use your meter. Some meters may need to be checked for accuracy with a control solution or strip. Others need specially coded test strips.

  • Test strips that are put into the blood glucose meter: When choosing test strips, make sure they work in the meter you are using. Look for strips that need only a small drop of blood and can draw the blood into the strip. If you have health insurance, make sure you know what types of strips your insurance will pay for before you choose your meter. The test strips are usually more expensive than the meter itself. Be sure you know how much test strips cost before you buy a meter.

How is the blood sugar test done?

To get a drop of blood:

  1. Wash your hands and the area you are testing with warm water and soap. This increases blood flow and makes sure there is nothing on the skin that may change the reading. It also helps prevent infection. Do not wipe the skin with alcohol. Any trace of alcohol left on the skin will interfere with the test. If you are away from home, you may use alcohol-free travel wipes to clean the area.
  2. Air dry the area completely before pricking your skin.
  3. Use the lancet to prick your skin.
  4. Put the drop of blood on the test strip. (If a test strip has been in a cooler or refrigerator, bring it to room temperature before you use it.) Make sure you completely cover the required area on the strip with blood. Putting too small a drop on the strip is a common mistake that causes inaccurate readings on your meter.
  5. Put the strip in the blood glucose meter to measure the sugar level.

Avoid incorrect blood sugar results by making sure:

  • Your meter is clean.
  • The test strip is not expired.
  • The meter is set up for the current box of test strips (run a control strip if necessary).
  • The meter and test strip are at room temperature.
  • The drop of blood is big enough.

Some meters are more accurate than others. If your blood sugar is very high or very low, test it a second time to double check the results. Talk to your provider about the accuracy of your meter.

When should I do a blood sugar test?

Your healthcare provider will tell you when and how often you need to check your blood sugar. Ask your healthcare provider what your blood sugar range should be. Also ask your provider to write down what you should do if your blood sugar result is too high or too low.

Some common testing times include first thing in the morning, before meals or exercise, 2 hours after meals, before driving, at bedtime, and any time you feel like your blood sugar may be too high or too low. You should also check your blood sugar when you are feeling ill.

You may need to test more often when your diabetes medicine, or any other medicines are changed. Certain medicines can affect blood sugar and how other medicines work.

Should I keep track of test results?

It is important to keep track of your blood sugar test results. Learning what affects your blood sugar can help you control it better. Keep separate records even if your meter stores results, in case the meter breaks. It’s a good idea to keep track of:

  • The date and time of the test
  • Any symptoms you have
  • The blood sugar value
  • If you exercised, were sick, or felt stressed.
  • What you ate before bedtime or exercise
  • When you have low blood sugar reactions and what you think might be possible causes

Always take your blood sugar records to checkups with your healthcare provider or diabetes educator.

Developed by RelayHealth.
Adult Advisor 2015.1 published by RelayHealth.
Last modified: 2015-02-10
Last reviewed: 2015-01-08
This content is reviewed periodically and is subject to change as new health information becomes available. The information is intended to inform and educate and is not a replacement for medical evaluation, advice, diagnosis or treatment by a healthcare professional.
Copyright ©1986-2015 McKesson Corporation and/or one of its subsidiaries. All rights reserved.

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