If you have diabetes, check your blood sugar level as often as instructed by your health care provider. Record the results. This will tell you how well you are managing your diabetes. Checking blood sugar can help you stay on track with your nutrition and activity plans.
The most important reasons to check your blood sugar at home are to:
- Monitor if the diabetes medicines you're taking increase your risk of low blood sugar (hypoglycemia).
- Use the blood sugar number before a meal to determine the dose of insulin (or other medicines) you are planning to take.
- Use the blood sugar number to help you make healthy nutrition and activity choices to regulate your blood sugar.
Check Your Blood Sugar Often
Not everyone with diabetes needs to check their blood sugar every day. Others need to check it many times a day.
Usual times to test your blood sugar are before meals and at bedtime. Your provider may ask you to check your blood sugar 2 hours after a meal or even sometimes in the middle of the night. Ask your provider when you should check your blood sugar.
Other times to check your blood sugar may be:
- If you are having symptoms of low blood sugar (hypoglycemia)
- After you eat out, particularly if you have eaten foods you don't normally eat
- If you feel sick
- Before or after you exercise
- If you have been under a lot of stress
- If you eat too much or skip meals or snacks
- If you are taking new medicines, took too much insulin or diabetes medicine by mistake, or took your medicine at the wrong time
- If your blood sugar has been higher or lower than normal
- If you are drinking alcohol
How to Prepare for the Test
Have all test items within reach before starting. Timing is important. Clean the needle prick area with soap and water. Completely dry the skin before pricking. Do not use an alcohol pad or swab to clean the skin. Alcohol is not effective in removing sugar residue from the skin.
How the Test is Done
You can buy a testing kit from a pharmacy without a prescription. Your provider can help you choose the right kit, set up the meter, and teach you how to use it.
Most kits have:
- Test strips
- Small needles (lancets) that fit into a spring-loaded plastic device
- A logbook for recording your numbers that can be downloaded and viewed at home or at your provider's office
To do the test, prick your finger with the needle and place a drop of blood on a special strip. This strip measures how much glucose is in your blood. Some monitors use blood from areas of the body other than the fingers, reducing discomfort. The meter shows your blood sugar results as a number on a digital display. If your vision is poor, talking glucose meters are available so that you don't have to read the numbers.
Be aware that no meter or strip is accurate 100% of the time. If your blood sugar value is unexpectedly high or low, measure again with a new strip. Do not use strips if the container has been left open or if the strip has gotten wet.
Keep a Record
Keep a record for yourself and your provider. This will be a big help if you are having problems controlling your diabetes. It will also tell you what you did when you were able to control your diabetes. To get the most help with controlling your blood sugar, write down:
- The time of day
- Your blood sugar level
- The amount of carbohydrates you ate
- The type and dose of your diabetes medicine
- The type of any exercise you do and how long you exercise for
- Anything unusual, such as stress, eating different foods, or being sick
Blood sugar meters can store hundreds of readings. Most types of meters can save readings to your computer or smart phone. This makes it easy to look back at your record and see where you may have had problems. Often the pattern of blood sugar changes from one time to another (for example, from bedtime to morning time). Knowing this is helpful for your provider.
Always bring your meter when you visit your provider. You and your provider can look at your blood sugar patterns together and make adjustments to your medicines, if needed.
You and your provider should set a target goal for your blood sugar level for different times of the day. If your blood sugar is higher than your goals for 3 straight days and you don't know why, call your provider.
Diabetes - home glucose testing; Diabetes - home blood sugar testing
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American Diabetes Association Professional Practice Committee. 6. Glycemic targets: Standards of medical care in diabetes-2022. Diabetes Care. 2022 Jan 1;45(Suppl 1):S83-S96. PMID: 34964868. pubmed.ncbi.nlm.nih.gov/34964868/.
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Review Date 2/1/2022
Updated by: Sandeep K. Dhaliwal, MD, board-certified in Diabetes, Endocrinology, and Metabolism, Springfield, VA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.