How to check your blood sugar at home — and the best testing devices to use
- To check your blood sugar, you can either use a glucose meter or a continuous glucose monitor.
- Glucose meters require several manual finger pricks throughout the day, while a continuous glucose monitor is attached to you and automatically measures blood sugar.
- Here's how to check your blood sugar with both devices and how often you'll need to do it.
- This article was medically reviewed by Jason R. McKnight, MD, MS, a family medicine physician and clinical assistant professor at Texas A&M College of Medicine.
For people with diabetes, it's necessary to check blood sugar on a daily basis. Luckily, it has become easier to check your blood sugar over time.
From the late 1940s to 1970s, diabetics had to measure blood sugar through urine, which was often messy and inaccurate. In the 1980s, blood sugar monitors allowed for much more precise and simple readings.
Monitoring your blood sugar still has its downsides, though. Error messages or malfunctioning devices could make you have to prick your finger multiple times. Yet despite the annoyance, new technology has helped make these measurements easier and easier.
Here's how to check your blood sugar at home, and which devices you should consider using to streamline the process.
How to check your blood sugar
Most commonly, people with diabetes check their blood sugar at home using one of two devices: a glucose meter or a continuous glucose monitor.
Glucose meters
A glucose meter is a small handheld device that you can use to manually check blood sugar. There are many different types of glucose meters, but they have two basic elements: a lancet, or a small needle, to draw blood from your finger, as well as a test strip to put in the device.
Since you'll need a drop of blood from a finger prick, here's how to do it safely and effectively:
1. Wash and dry your hands thoroughly before using the glucose meter.
2. Wipe the area with an alcohol pad to disinfect it.
3. Prick your finger with the lancet and squeeze out a drop of blood.
4. Put the blood on the test strip.
5. Insert the test strip into the glucose meter and follow the instructions on the screen.
Once the meter processes the blood, it measures your blood sugar. Most devices give results in seconds on the machine's digital screen. To understand your results, learn more about what a normal blood sugar level should look like for you.
You'll also want to record and track your blood sugar levels over time. Some people may opt for a manual log through a digital spreadsheet or written paper record. But there are also different programs you can buy, such as Glooko and Tidepool, to help you automatically monitor and share your blood sugar measurements with your doctor.
Continuous glucose monitors
Continuous glucose monitors, or CGMs, measure glucose levels under the skin and are attached as wearable devices to the arm or belly. They allow patients to see their glucose levels throughout the day, since their glucose data is collected every few minutes and sent wirelessly to tracking software.
One part of a CGM is the data sensor and transmitter, which is inserted under the skin. Sensors monitor the glucose in the interstitial fluid underneath the skin to track blood sugar continuously.
Many CGMs alert users when blood sugar is too high or too low. You'll need to replace the sensor every three to 14 days, depending on the model.
Nestoras Mathioudakis, MD, a diabetes expert at Johns Hopkins Medicine, says that CGMs are the most effective devices for patients with diabetes, as knowing glucose levels in real time can help you make more informed decisions on the types of food to eat and how much insulin medication to take.
Though the machine monitors glucose levels under the skin, people with CGMs must make sure their machine works properly twice a day, using a glucose meter to make sure the numbers on the meter and the CGM are the same. Still, a CGM requires fewer finger pricks than a glucose meter.
When should you check blood sugar?
If you have diabetes, at home tests should be done before a meal, one to two hours after a meal, and at bedtime. Type 1 and type 2 diabetics who use insulin medication should check their blood sugar at least four times a day.
For those who have prediabetes, or at risk for developing diabetes, your blood sugar should be checked through routine blood work at a yearly doctor's exam. If you're not at risk for diabetes, glucose levels can be checked every three years.
"I wouldn't recommend that the general public be checking their blood glucose to figure out what their risk is," says Mathioudakis. "But certainly people with diabetes, and especially people with diabetes that have medications that can really lower their blood glucose, they should be checking."
For more information, read our article about on what's considered healthy and normal blood sugar levels.