How to Use a Glucometer

A glucometer is a small, portable device that lets you check your blood sugars (glucose levels) at home. No matter what type of diabetes you have, a glucometer can give you valuable information. 

Also called glucose meters, these devices can tell you in seconds if your blood sugar is too low, too high, or on target. Regular monitoring helps you manage your diabetes, but it's important to use your glucometer the right way.

Person using glucometer

 

Karl Tapales / Getty Images

This article looks at how glucometers work, who should use them, when and how to test, target ranges, and how to help a child test their blood sugars.

Who Should Use a Glucometer?

You may need to use a glucometer regularly if you have:

Frequent glucometer use can help you:

  • Check your blood sugar levels and overall control
  • See how your glucose levels respond to exercise or stress
  • Recognize what else makes your levels spike or crash
  • Monitor the effects of medications and other therapies
  • See how well you're meeting treatment goals

Glucose control is important because of both short-term and long-term health consequences of unmanaged diabetes.

When to Test

Talk to your doctor about when and how often you should test your blood sugars. Make sure you know what to do if your results are low or high. 

Your testing frequency may depend on your type of diabetes and your treatment plan. Your healthcare provider will tell you what testing schedule is best for you. That schedule may or may not be similar to the general guidelines.

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Type 1 Diabetes

Insulin is a hormone produced by the pancreas. It helps your cells use the glucose in your blood. In type 1 diabetes, the pancreas stops making insulin or makes very little.

That makes frequent testing important. It helps ensure you have enough insulin to keep your blood sugar levels stable. If you have type 1 diabetes, you may need to test your glucose levels four to 10 times per day.

You may test:

  • Before eating (meals and snacks)
  • Before and after exercise
  • Before bed
  • Possibly during the night

If your routine changes or you get sick, you may need to test even more often.

Type 2 and Gestational Diabetes

In type 2 and gestational diabetes (GD), your body still produces insulin, but it doesn't use it efficiently. This is called insulin resistance and it makes blood sugar levels rise.

If you one of these conditions, you may only need to test two to four times per day. You may test much more often, though, especially when your diagnosis is new and your levels aren't yet stable.

You may check:

  • First thing in the morning and before bed
  • Before each meal and before bed
  • Before and two hours after each meal and before bed

In part, this depends on whether you take insulin or use other medications. If you manage your diabetes with non-insulin medication and know your typical patterns, you may not even need to test daily.

Target Glucose Ranges

General guidelines for target glucose levels may or may not apply to you. Your healthcare provider can tell you the ideal range for you. Levels can vary depending on:

  • Age
  • Sex
  • Activity level
  • Type of diabetes
  • How long you've had diabetes
  • Other health conditions

The American Diabetes Association says the following target range applies to most non-pregnant adults with diabetes.

Pre-meal blood sugar 80 to 130 mg/dL
Post-meal blood sugar Less than 180 mg/dL

Supplies You Need

Before you use your glucometer, make sure you have all the necessary supplies:

  • Alcohol prep pad or soap and water
  • A lancing device with a fresh lancet (used to draw blood)
  • A test strip
  • A way to record results

You'll need to use test strips specially made to work with your glucometer. Also, the lancets need to be the right design for your lancing device.

Using a Glucometer: Step-by-Step

Glucometers only need a drop of blood. The meters are small enough to travel with or fit in a purse. You can use one anywhere.

Each device comes with an instruction manual. And typically, a healthcare provider will go over your new glucometer with you too. This may be an endocrinologist or a certified diabetic educator (CDE), a professional who can also help develop an individualized care plan, create meal plans, answer questions about managing your disease, and more.

These are general instructions and may not be accurate for all glucometer models. For example, while the fingers are the most common sites to use, some glucometers allow you to use your thigh, forearm, or the fleshy part of your hand. Check your manual before using the device.

how to use a glucometer

Verywell / Hugo Lin

Before You Start

Prepare what you need and wash up before drawing blood:

  • Set out your supplies
  • Wash your hands or clean them with the alcohol pad. This helps prevent infection and removes food residue that might alter your results.
  • Allow the skin to dry completely. Moisture can dilute a blood sample taken from the finger. Don't blow on your skin to dry it, as that can introduce germs.

Getting and Testing a Sample

This process is quick, but doing it right will help you avoid having to re-stick yourself.

  1. Turn on the glucometer. This is usually done by inserting a test strip. The glucometer screen will tell you when it's time to put blood on the strip.
  2. Use the lancing device to pierce the side of your finger, next to the fingernail (or another recommended location). This hurts less than lancing the pads of your fingers.
  3. Squeeze your finger until it has produced a sufficent-size drop.
  4. Place the drop of blood on the strip.
  5. Blot your finger with the alcohol prep pad to stop the bleeding.
  6. Wait a few moments for the glucometer to generate a reading.

If you often have trouble getting a good blood sample, warm your hands with running water or by rubbing them briskly together. Be sure they are dry again before you stick yourself.

Recording Your Results

Keeping a log of your results makes it easier for you and your healthcare provider to build a treatment plan.

You can do this on paper, but smartphone apps that sync with glucometers make this very easy. Some devices even record readings on the monitors themselves.

Follow your doctor's orders for what to do based on the blood sugar reading. That may include using insulin to bring your level down or eating carbohydrates to bring it up.

Lancet Disposal

Dispose of lancets in a sharps container. Ask your healthcare provider or pharmacy for one or use a thick, plastic bottle with a screw-on cap. Take the container to a hospital or pharmacy with a drop-off program or check disposal regulations where you live.

Avoiding Common Problems

Properly maintaining and using your glucose meter can help you avoid incorrect readings, insufficient samples, and your monitor not working when you need it to.

You should:

  • Keep extra glucometer batteries on hand.
  • Don't use expired test strips. They can give inaccurate results. 
  • Store strips in their container with the lid tightly closed. Light or moisture can cause damage.
  • Clean your device at regular intervals. Run quality-control checks when prompted. (Check your manual for how.)
  • Some devices require larger blood samples. Be sure to use the blood sample size required by your device.

Lancet Pain

If lancing your finger is painful, you have a few options for making it hurt less:

  • Use a fresh lancet: Not only is a new lancet required for every use due for hygiene purposes, but repeated use dulls them and makes pokes more painful.
  • Change the gauge (thickness) of your lancets: The higher the number on the packaging, the thinner the lancet. A 30-gauge lancet, for example, may be more comfortable than a 21-gauge one.
  • Adjust the setting on your lancing device: This can make the poke less deep. Try a low setting, such as 2 or 3, and then work your way up until you get a good sample with minimal pain.
  • Alternate the finger, and which side of the finger, you use. That will give the spots time to heal before you poke them again.

Glucose Testing On-the-Go

When traveling, be sure to pack extra test strips, lancets, and other supplies like insulin, needles, and batteries.

  • Keep your glucometer and test strips in a clean, dry place.
  • Avoid extreme temperatures and direct sunlight. Don't leave your supplies in your car or put them in checked baggage.
  • If you're traveling for several days, a hard plastic pencil case makes a good temporary sharps container.

If you're flying, check TSA rules for carrying your supplies and medications.

Glucose Monitoring in Children

Kids with diabetes of any type need to check their glucose levels, too. Children may need to test more often than adults, especially if they use insulin.

Getting your child get familiar with regular glucose testing can help with:

  • Troubleshooting problems in the treatment plan
  • Giving them a feeling of control over what's happening
  • Their understanding of how food, exercise, and medication affect blood sugar

Children may also have higher glucose target ranges than adults. Their healthcare provider can tell you what a child's ideal range is.

Children who have hypoglycemia or low blood sugar episodes may need to be tested in the middle of the night.

Extra testing may also be required when your child is sick.

Helping Kids Self-Test

Practice using the glucometer with your child often. Empowering them with the tools and know-how they need will help when they transition to taking care of themselves.

Teach your child that glucose self-testing is a big responsibility. Let them know how important it is for managing their condition as they grow older and more independent.

Continuous Glucose Monitoring: An Alternative

Because you need to test your sugars more often if you have type 1 diabetes, you may want to look into a continuous glucose monitor (CGM) rather than a traditional glucometer.

With a CGM, a tiny sensor is inserted under your skin. It usually goes in the:

  • Upper arm
  • Abdomen
  • Thigh

The sensor transmits a glucose readout to a special monitoring device or smartphone, usually every five to 15 minutes.

Because the sensor is not replaced for several days, this technology reduces—but may not eliminate—the need for finger pricks.

Ask your healthcare provider if a CGM is right for you.

Summary

Glucometers help you monitor your blood sugar levels. They are used by people with type 1, 2, LADA, and gestational diabetes.

Your healthcare provider can tell you how often to test and what your target ranges are.

Use and maintain your glucometer as directed by the manual. If you need help, ask your healthcare provider about seeing a certified diabetic educator.

Frequently Asked Questions

  • How does a glucometer work?

    To get a reading, prick your fingertip and place a drop of blood on a plastic test strip inserted into the glucometer. The meter then gives you a reading. 

  • Why do I need to monitor my blood sugar throughout the day?

    Blood sugars fluctuate so frequent monitoring is the best way to get your diabetes under control. Poor control means greater health risks, including kidney disease, vision loss, heart disease, and other health problems.

  • What is continuous glucose monitoring?

    A continuous glucose monitor has a tiny sensor that's inserted under your skin. It checks your blood sugar level every few minutes around the clock and sends results to a remote monitor. This gives you the ability to monitor levels without multiple finger pricks.

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8 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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  2. Centers for Disease Control and Prevention. Diabetes: What is type 1 diabetes?

  3. Centers for Disease Control and Prevention. Diabetes: Type 2 diabetes.

  4. Association of Diabetes Care & Education Specialists. How a diabetes care and education specialist can help you.

  5. Centers for Disease Control and Prevention. Diabetes: Monitoring your blood sugar.

  6. University of Florida Diabetes Institute. Getting rid of used needles, syringes, and lancets.

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  8. UpToDate. Patient education: Blood glucose monitoring in diabetes (Beyond the basics).

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