Blood Glucose Monitoring: How It Works - Healthline

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HealthlineSubscribeYour Guide to Monitoring Blood Sugar

Medically reviewed by Victoria Bouhairie, MD, DABOM, DipABLM — Written by Brian Krans — Updated on September 8, 2025

Supplies
Preparation
Procedure
Understanding results
Benefits
Risks
Summary

Blood glucose monitoring is an essential tool for managing diabetes. It helps identify how your blood sugar levels respond to factors like diet, exercise, and medications so you can change your diabetes management plan as needed.

Checking your blood sugar level is one of the best ways to understand your diabetes. It helps you identify and track how different foods, medications, and activities affect your glucose levels.

Keeping track of your blood glucose levels over time can also help you and your doctor make any necessary adjustments to your diabetes management plan.

Here’s everything you need to know in order to get started.

What supplies are needed for blood glucose monitoring?

Most people who have diabetes use portable blood glucose meters called glucometers to check their blood sugar levels. These meters work by analyzing a small amount of blood, usually from a fingertip.

A lancet (tiny needle) lightly pricks your skin to obtain the blood, and a meter tells you your current blood sugar level. But because blood sugar levels change, you need to check your levels often and record them.

You can get blood glucose monitoring kits and supplies from:

your doctor’s office
a diabetes educator’s office
a pharmacy
online stores

You can discuss the price with your doctor or pharmacist. Glucose meters come with testing strips, lancets to prick your finger, and a device to hold the needle. The kit may include a logbook, or you might be able to download the readings onto a computer.

Meters vary in cost and size. Some have added features to suit different needs and preferences. These may include:

audio capabilities for people with low or no vision
backlit screens that are easier to read in low light
additional memory or data storage
preloaded test strips for people who have difficulty using their hands
USB ports to load information directly onto a computer

How to prepare for blood glucose monitoring

Before checking your blood glucose levels, make sure you have:

a finger-stick device, such as a lancet, to prick your finger
an alcohol swab to sterilize the puncture site
a blood glucose monitor
a bandage in case bleeding continues beyond a few drops

Also, depending on the type of test you’re taking and your doctor’s instructions, you may need to adjust your medication or meal schedule or schedule the test around these factors.

How is blood glucose monitoring performed?

Before you begin, wash your hands thoroughly to prevent infection at the finger-prick site. If you use alcohol wipes instead of washing, be sure to let the site dry before testing.
Put a testing strip into the meter. Prick your finger with the lancet to get a small drop of blood. To decrease the discomfort in your finger, you can use the side of your fingertip instead of the tip.
Apply some blood to the test strip you inserted into the meter. Your meter will analyze the blood and give you the blood glucose reading on its digital display, usually within a minute.

Finger pricks rarely require a bandage, but you may want to use one if bleeding continues beyond a few drops. It’s important to follow all the instructions that come with your glucometer to ensure accurate results.

If you have type 1 diabetes, you may need to test your blood glucose four or more times per day, including before and after meals and exercise. You may need to test more often when you are sick.

If you have type 1 or type 2 diabetes, your doctor will let you know when and how often to test your blood glucose.

Understanding results of blood glucose monitoring

According to the American Diabetes Association, most adults with type 1 or type 2 diabetes who are not pregnant should aim for blood sugar levels in the following ranges:

Time	Recommended blood sugar range
fasting (before a meal)	80 to 130 mg/dL
1–2 hours after a meal	less than 180 mg/dL

But these are general guidelines and are not for everyone. Ask your doctor about your individual target levels.

Regular blood glucose monitoring is an essential tool to help you manage your diabetes. By identifying and recording changes in your blood sugar levels, you’ll have more information about how food, exercise, stress, and other factors affect your diabetes.

What are the benefits of blood glucose monitoring?

Regular glucose monitoring is one way you can learn more about how your body responds to diabetes management.

When it’s time to make important decisions about medication dosage, exercise, and diet, knowing your blood glucose levels will be helpful to you and your healthcare team.

By checking your blood glucose levels routinely, you’ll also know when your blood sugar is too high or too low, either of which can cause symptoms and serious health problems.

Your doctor will calculate your target blood glucose range based on your age, your type of diabetes, your overall health, and other factors. It’s important to keep your glucose levels within your target range as best as you can.

Complications of high and low blood sugar levels

Without proper treatment, high blood sugar levels can lead to long-term complications, such as:

heart disease
nerve damage
vision problems
poor blood flow
kidney disease

Low blood sugar levels can also cause symptoms, including:

confusion
weakness
dizziness
jitters
sweating
palpitations (fast heartbeat)

Additionally, low blood sugar can lead to serious complications like seizures and coma.

If you experience any of these symptoms of low blood sugar levels, you’ll need prompt medical attention.

What are the risks of blood glucose monitoring?

Risks from the blood glucose test are minimal and much less significant than the risks of not monitoring your blood sugar levels.

You should never share needles or finger-stick devices for any reason. Sharing testing supplies with someone can increase your risk of contracting or transmitting viruses, such as:

HIV
hepatitis B
hepatitis C

Takeaway

Regular blood glucose monitoring is a way to gather information about how your blood sugar levels respond to your day-to-day activities. These readings can help you and your doctor make informed decisions about your diabetes management plan.

How we reviewed this article:

SourcesHistoryHealthline has strict sourcing guidelines and relies on peer-reviewed studies, academic research institutions, and medical journals and associations. We only use quality, credible sources to ensure content accuracy and integrity. You can learn more about how we ensure our content is accurate and current by reading our editorial policy.

Blonde L, et al. (2022). American Association of Clinical Endocrinology clinical practice guideline: Developing a diabetes mellitus comprehensive care plan—2022 update. https://www.endocrinepractice.org/article/S1530-891X(22)00576-6/fulltext
Considerations for blood glucose monitoring and insulin administration. (2024).https://www.cdc.gov/injection-safety/hcp/infection-control/
Hypoglycemia (low blood glucose). (n.d.).https://diabetes.org/living-with-diabetes/treatment-care/hypoglycemia
Check your blood glucose | Diabetes testing & monitoring. (n.d.).https://diabetes.org/living-with-diabetes/treatment-care/checking-your-blood-sugar

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Medically reviewed by Victoria Bouhairie, MD, DABOM, DipABLM — Written by Brian Krans — Updated on September 8, 2025

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