Health Library

Why Check Blood Sugars?

Checking your child’s blood sugar tells you the amount of glucose (glucose level) in your child’s blood and is a key part of daily care. Each time you check, you will know if your child’s blood sugar is inside or outside the healthy range set by the care team. 

Checking blood sugars regularly can help you and your child:

• Feel more in control of diabetes.
• Find out how food, exercise, and diabetes medicine affect the blood sugar.
• Know when you need to make any changes to food, exercise, and diabetes medicines.
• Manage sick days.
• Prevent health problems that can happen now or in the future.

When Should I Check My Child’s Blood Sugar?

The diabetes care team will tell you when to check your child’s blood sugar. Most kids and teens need to test:

• before each meal
• at bedtime
• before, during, and after exercise

Sometimes you may need to test more often, even while your child sleeps. For example, if:

• Your child was recently diagnosed with diabetes.
• Your child is sick.
• Your child is having a lot of high or low blood sugars.
• There are changes in your child’s diabetes treatment or daily habits.

What Do I Use to Check the Blood Sugar?

Two kinds of devices can test blood sugar or glucose levels:

• a blood glucose meter measures the amount of glucose in the blood
• a continuous glucose monitor measures the amount of glucose just beneath the skin in the fluid around the cells

Your child’s care team can tell you which device is best for your child.

What’s a Blood Glucose Meter?

A blood glucose meter is a small, portable machine that measures the amount of glucose in the blood. You place a drop of blood taken from a fingerstick and put it on a test strip, which you insert into the meter. The meter tells your child’s blood sugar now, as you do the test.

Many types of meters are available. The care team will help you find the meter that is best for your child, and they’ll show you how to use it. Blood glucose meters vary by:

• Cost. Ask your insurance company which blood glucose meters they cover. It’s also good to ask about your coverage for test strips.
• User-friendliness. Choose a meter that is easy to use and take care of.
• Special features. Meters come in different sizes. Some can store extra information like dates, times, food intake, and exercise. Others can download readings so your provider can easily see this information. 

What’s a Continuous Glucose Monitor (CGM)?

A continuous glucose monitor is a wearable device that measures glucose every few minutes, all day and night. A CGM uses a thread-like sensor that’s put under the skin and secured in place. Sensors can stay in place for 10–14 days (depending on the product) before you replace them.

Instead of measuring glucose in the blood directly, a CGM measures the amount of glucose (glucose level) just beneath the skin in fluid surrounding the cells, called the interstitial fluid. Here’s how it works: As we digest carbohydrates, glucose enters the bloodstream. Then, it moves into the interstitial fluid on its way to all the cells in the body. It takes a little time for the glucose to move from the bloodstream into the interstitial fluid, so a glucose measurement taken with a CGM will be 5–10 minutes behind a blood glucose measurement. The benefit of a CGM is that because it measures glucose so often, it gives a more complete picture of how a person’s glucose level changes throughout the day.

People with diabetes often choose a CGM because:

• It is convenient. You rarely need to do fingersticks. The CGM can get wet, so your child can bathe and swim with it.
• It tells you the bigger picture. Because a CGM takes measurements every few minutes, you get a more detailed picture of your child’s glucose level and whether it is going up or down and how fast. This helps you and the care team keep sugars in the healthy range.
• It gives piece of mind. The CGM can send your child’s glucose levels to a smart device unless you are using a receiver. That means you can know if your child’s glucose is in the healthy range even when they are at school or asleep. Using the alarm feature can notify you if the glucose is heading out of the healthy range.

What Happens With the Test Results?

Your child’s health care team can look at the data online when you need them to or at clinic visits. They will review your child’s glucose levels to look for patterns, like high or low sugars at certain times of the day. Patterns can help the doctor adjust medicines and the dietitian make diet changes.

If your child’s glucose level is higher or lower than you expect from time to time, try not to get discouraged. Ask your child’s care team if there are some changes you should try. Together you’ll figure out the best way to keep your child’s sugar in the healthy range as much as possible.