How to Use a Glucometer

Diabetic girl using blood glucose meter
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Whether you have type 1 or type 2 diabetes, at-home blood-sugar monitoring devices called glucometers can give you valuable information about whether your blood sugar is too low, too high or in a good range for you. These portable electronic devices provide you with instant feedback and let you know immediately what your blood sugar is. Regular monitoring is a particularly helpful way to manage your diabetes and help control your blood sugar, so it's important to know how to properly use the device.

About Glucometers

Glucometers, also known as glucose meters, are highly sophisticated, requiring only a single drop of blood, and are conveniently sized and portable. They are small enough to take with you on-the-go, and based on your comfort level, can be used anywhere at any time.

Who Should Use a Glucometer

If you have type 1 diabetes, type 2 diabetes, latent autoimmune diabetes in adults (LADA), or were diagnosed with gestational diabetes during pregnancy, a major part of your treatment plan should be regularly testing your blood glucose levels with a glucometer.

Frequent glucometer use can help you:

  • Check how controlled your blood sugar is and whether it's high or low
  • Recognize patterns when you're more likely to have a spike or crash in glucose
  • See how your glucose levels respond after exercise or in times of stress
  • Monitor the effects of diabetes medications and other therapies
  • Assess how well you're meeting specific treatment goals

Keeping a record of your glucometer results can help you pattern manage—providing you with information on how your body is responding to certain foods, exercise, and medicine. It also provides your doctor with an accurate picture of how your treatment is working.

When to Test

Discuss with your doctor how often and at what times of the day you should be testing and what to do if your results are low or high. Your testing frequency may depend on your specific type of diabetes and your personal treatment plan.

Type 1

Generally speaking, if you have type 1 diabetes, you may need to test your glucose levels four to 10 times per day. You'll likely test before you consume any food (meals or snacks), before and after you exercise, before bed, and possibly during the night. Because your condition is marked by an inability to produce adequate insulin, you'll have to check more frequently to make sure you have enough insulin to keep your blood sugar stable. If your routine changes or if you become sick, you may need to test even more times throughout the day/night.

Type 2

If you have type 2 or gestational diabetes, you may only need to test two to four times per day, depending on whether you take insulin or not. Generally, you should test before meals and at bedtime. If you're managing your diabetes with noninsulin medication, you may not even need to test your sugar daily once you've learned your typical patterns.

How to Use a Glucometer

Oftentimes, unless you have met with a certified diabetes educator, your doctor may have given you a prescription for a glucometer without explicitly telling you how to use it. And while most instruction manuals are user-friendly, this task can seem daunting if you are new to testing or not that technologically savvy. Follow these guidelines for safe and easy testing.

What You Need to Use a Glucometer

  • Alcohol prep pad (or soap and water if you have access to a sink)
  • Lancet
  • Test strip
  • Glucometer
  • A notebook to record results

Glucometer Usage Instructions

  1. First, set out your glucometer, a test strip, a lancet, and an alcohol prep pad.
  2. Wash your hands to prevent infection. If you are not by a sink, it's okay to just use the alcohol swab. If you are by a sink and wash your hands thoroughly, you do not have to use an alcohol swab. 
  3. Sometimes it helps to warm your hands first to make the blood flow easier. You can rub your hands together briskly or run them under warm water—just be sure to dry them well as wet hands can dilute the blood sample, resulting in a lower number. 
  4. Turn on the glucometer and place a test strip in the machine when the machine is ready. Watch the indicator for placing the blood on the strip.
  5. Make sure your hand is dry and wipe the area you've selected with an alcohol prep pad and wait until the alcohol evaporates.
  6. Pierce your fingertip on the side of your finger, between the bottom of your fingernail to the tip of your nail (avoid the pads as this can pinch more). The type of drop of blood required is determined by the type of strip you are using (some use a "hanging drop" of blood versus a small drop for strips that draw blood in with a capillary action).
  7. Place the drop of blood on or at the side of the strip.
  8. The glucometer will take a few moments to calculate the blood sugar reading. Follow your doctor's orders for whatever blood sugar reading you get.
  9. You may use the alcohol prep pad to blot the site where you drew the blood if it is still bleeding.
  10. Write down your results. Keeping a record makes it easier for you and your doctor to establish a good treatment plan. Some glucometers can store your results in a memory, for easier record keeping.

Keeping a record of your results can help you pattern manage—providing you with information on how your body is responding to certain foods, exercise, and medicine. It also provides your doctor with an accurate picture of how your treatment is working.

Continuous Glucose Monitoring

People with type 1 diabetes may need to test their sugars more frequently, and in these situations, a continuous glucose monitor (CGM) can be very helpful. A CGM is a glucometer that stays attached to your body, reducing (though not fully eliminating) the need for multiple fingerpricks. You'll simply affix a sensor to your skin (usually in your upper arm, abdomen, or thigh), and it will transmit a glucose readout at predetermined intervals—usually every few minutes—to a monitoring device. Ask your doctor if a CGM is right for you.

Target Ranges

While your personalized target range may be slightly narrower, there are established windows as to what's considered normal glucose levels for most people with diabetes. Your levels may vary depending on your age, activity level, sex, and type of diabetes.

According to the American Diabetes Association, the following target range is applicable for most nonpregnant adults. Target hemoglobin A1c (a test that measures an average of your blood sugar over the past two to three months) ranges may differ depending on age/sex and other factors.

Marker Target Value  
Preprandial blood glucose (pre-meal) 80 to 130 mg/dL  
Postprandial blood glucose (post-meal) Less than 180 mg/dL  
A1c Less than 7%  

First-Time Testing Tips

Be sure to review the owner's manual provided with your glucometer, as testing procedures may vary slightly between devices. Here are a few more helpful tips for first-timers:

  • If you're finding the process very painful, you might need to change your lancet gauge (thickness). Lancets come in different gauges. The higher the number, the thinner the lancet. A 21 gauge lancet may not be as comfortable as a 30 gauge lancet.
  • You can also adjust the setting on your lancing device to depict how far the needle will penetrate the skin. Most people can retrieve an adequate sample from somewhere in the middle. For example, if your lancet is numbered, adjust it to setting number 2. If that doesn't work you can increase the setting. 
  • Only use test strips that are designed for your glucometer.
  • Some devices require larger blood samples—be sure to use the blood sample size as required by your device.

Common Problems to Avoid

It's important to regularly maintain your glucose meter to avoid potential problems. Follow these tips to ensure good functioning:

  • Make sure you keep batteries in stock that fit your glucometer.
  • Make sure your test strips are not expired, as expired test strips can provide an inaccurate result. 
  • After taking a test strip out, close the lid tightly. Too much light or moisture can damage the strip. 
  • Clean your device at regular intervals and run quality-control checks when prompted.

Glucose Testing On-the-Go

When you're traveling, you may need to take extra supplies and use extra care to ensure your glucose meter will continue to function properly.

  • Whenever you're testing on-the-go, be sure you have twice as many test strips and lancets as you think you'll need, just in case.
  • Keep your glucometer and test strips in a clean, dry place. And avoid extreme temperatures. For example, do not leave your meter and strips in your car when it is cold out or in direct sunlight or on top of your heater
  • Dispose of your lancets in a puncture-proof container, preferably a red sharps container that is made for that purpose. You can get one from your doctor or pharmacy. If none is available, use a thick, plastic laundry detergent bottle with a screw-on cap, to prevent needle-stick accidents. Many hospitals and pharmacies have a sharps drop-off program where you can bring your container when it is full.
  • If you're traveling for several days, bring a hard plastic pencil case with you to store your discarded lancets in and bring them back with you until you can properly dispose of them.
  • Make sure you always have a small stash of fast-acting carbohydrate snacks, extra insulin, or additional medication in case of emergency.

Tips for Kids

It's just as important for kids with diabetes (type 1 or type 2, though type 1 is more common) to regularly test their glucose levels, too.

Getting your child familiar with regular glucose testing has the following benefits:

  • Troubleshooting problems in the treatment plan
  • A feeling of control over what's happening
  • Understand the impact of certain food, exercise, and medications on blood sugar

Children may need to test more frequently than adults, especially if they take insulin. Children may also have higher glucose target ranges than adults. Speak with your child's physician about their unique target range. Children having issues with hypoglycemia episodes may need testing during the middle of the night, and also during sick days. Glucose level record-keeping may be especially helpful for children to start to see trends of how their blood sugar levels spike and crash after certain factors, such as different foods, physical activity, and medications.

Helping Kids Self-Test

Practice using the glucometer often with your child, and when your child is old enough, they may be able to start testing by themselves. Empower them with the tools and know-how needed to effectively take care of themselves. Help your child understand that glucose self-testing is a big responsibility—and one that is highly useful in managing their condition as they grow older and more independent.

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