Most people with diabetes should test their blood sugar (or blood glucose) levels regularly. Knowing the results lets you adjust your strategy for keeping the disease in check.
Regular testing can also help you avoid getting long-term health problems that can stem from the condition, like:
- Heart disease
- Stroke
- High blood pressure
- High cholesterol
- Blindness
- Kidney disease
- Skin problems
Research shows that in people with either type 1 or type 2 diabetes, sticking to your target blood sugar and HbA1c levels makes complications less likely.
Types of Blood Sugar Tests
A blood sugar test measures the level of sugar (glucose) in your blood. Most people with diabetes should test their blood sugar levels regularly. Knowing the results lets you adjust your strategy for keeping the disease in check. There are different ways to do the test, including:
Glucometers
A glucose meter, or glucometer, is a portable machine that can measure your blood sugar level from a small sample of your blood. You access your blood in different ways with different types of glucometers.
From your fingertip: You prick your finger with a small, sharp needle (called a lancet) and put a drop of blood on a test strip. Then you put the test strip into a meter that shows your blood sugar level. You get results in less than 15 seconds and can store this information for future use. Some meters can tell you your average blood sugar level over a period of time and show you charts and graphs of your past test results. You can get blood sugar meters and strips at your local pharmacy.
Meters that test other sites: Newer meters let you test sites other than your fingertip, such as your upper arm, forearm, base of the thumb, and thigh. You may get different results than from your fingertip. Blood sugar levels in the fingertips show changes more quickly than those in other testing sites. This is especially true when your blood sugar is rapidly changing, like after a meal or after exercise. If you are checking your sugar when you have symptoms of hypoglycemia, you should use your fingertip if possible, because these readings will be more accurate.
Continuous glucose monitoring system: These devices, also called interstitial glucose measuring devices, are combined with insulin pumps. They are similar to finger-stick glucose results and can show patterns and trends in your results over time. There are different kinds of CGM systems. Some are separate devices, and others are attached to an insulin pump.
HbA1c home tests
Hb stands for hemoglobin, which is the protein inside red blood cells that carries oxygen. When your blood sugar is high, more sugar binds to hemoglobin, so an HbA1c test can give you an estimate of the average amount of glucose in the blood over time. To take an HbA1c test, you prick your finger and put a drop of blood on a test strip for a reading. Some HbA1c tests involve mailing your blood sample to a lab.
At-home HbA1c tests aren’t as accurate as lab tests, but they can be helpful if in-person visits with a doctor aren’t easy for you because of distance or other reasons. You can report your results to a doctor from home so they have an idea of how your blood sugar is doing.
Laboratory tests for diabetes
Your doctor may recommend you take a laboratory test for your diabetes. Options include:
Fasting blood sugar test. Your doctor will ask you not to drink or eat for 8-12 hours before this test. In a clinic, a technician will either prick your finger or draw blood from a vein in your arm using a needle and test the result in a lab. Your fasting blood glucose level should be the lowest level you have. A normal result is under 99 milligrams per deciliter (mg/dL). If your results are higher, it’s a sign that you have prediabetes or diabetes.
Oral blood glucose test. Doctors also call this a glucose tolerance test. It measures your body’s response to sugar. For this test, your doctor will have you drink a syrupy glucose solution that has 75 grams of sugar. A technician will take a blood sample an hour later and 2 hours later to see how your body has processed the sugar. A healthy blood glucose level, 2 hours after you drink the solution, is lower than 140 mg/dL.
HbA1c. Like the home HbA1c test, this test estimates your average blood glucose levels over a period of time. For the test, a doctor collects a blood sample by drawing blood from a vein in your arm and sends the sample to a lab for testing.
When to Test Blood Sugar
You may need to check your blood sugar several times a day, such as before meals or exercise, at bedtime, before driving, and when you think your blood sugar levels are low.
Everyone is different, so ask your doctor when and how often you should check your blood sugar. If you're sick, you'll probably need to test your blood sugar more often.
What Affects Blood Sugar Test Results?
Having certain conditions, like anemia or gout, can affect your blood sugar levels. Other conditions can make a difference in your results, too, such as:
- Hot or humid weather
- High altitude
- Dehydration
- Infection or other illness
- Stress
- Food
- Certain medications
- Poor sleep quality
If you keep seeing unusual results, recalibrate your meter and check the test strips.
The chart below gives you an idea of where your blood sugar level should be throughout the day. Your ideal blood sugar range may be different from another person's and will change throughout the day.
| Time of Test | Ideal for Adults With Diabetes |
| Before meals | 80-130 mg/dL |
| After meals | Less than 180 mg/dL |
Home blood glucose monitoring and HbA1c
Monitoring your HbA1c level is also important for diabetes control. Many home glucose monitors also display an average blood glucose reading, which can correlate with your HbA1c.
Average Blood Glucose Level (mg/dL) | HbA1c (%) |
126 | 6 |
154 | 7 |
183 | 8 |
212 | 9 |
240 | 10 |
269 | 11 |
298 | 12 |
When Should I Call My Doctor About My Blood Sugar?
Ask your doctor about your target blood sugar range, and make a plan for how to handle blood sugar readings that are either too high or too low and when to call your doctor. Learn about the symptoms of high or low blood sugar, and know what you can do if you begin to have symptoms.
How Do I Record My Blood Sugar Test Results?
Keep good records of any blood, urine, or ketone tests you do. Most glucose monitors also have a memory. Your records can alert you to any problems or trends. These test records help your doctor make any needed changes in your meal plan, medicine, or exercise program. Bring these records with you every time you see your doctor.
Some devices send your readings to a computer or mobile device, making it easy to share the data directly with your diabetes care team.
As you’re recording your blood sugar, make a note of your diet and movement (even activities like gardening can make a difference) around the time of your reading. This will give you a fuller picture of what’s affecting your levels and better inform how to keep them steady in the future.
How to Test Blood Sugar at Home Accurately
To ensure you’re getting the most accurate read on your blood sugar, be sure you’re doing your testing correctly. Follow these tips:
- Use your device according to your doctor’s instructions.
- Use only the test strips made for your testing method.
- Store your testing materials correctly.
- Make sure your testing strips aren’t expired.
- Clean your device regularly.
- Have your doctor check your testing device from time to time to make sure it’s working well.
- Wash and dry your hands well before you test.
Takeaways
Testing your blood sugar is one of the most important tools for managing diabetes. You can monitor blood sugar at home with glucose meters and test strips, continuous glucose monitoring systems, and HbA1c tests. Your doctor will help you know what your target range should be and what may affect your readings.
Blood Sugar Test FAQs
Should I check my blood sugar if I have diabetes?
Monitoring your blood sugar levels is one of the most important parts of diabetes management. Knowing your blood sugar levels informs your daily treatment and helps you keep your levels as steady as possible as you make choices about what to eat and do during the day.
What should your blood sugar level be if you have diabetes?
Target blood sugar levels vary by person. Your doctor will be able to tell you the healthiest range for your age, size, lifestyle, and other medical conditions. Your target range may also change as you age. In general, most (non-pregnant) adults should have a range of 80-130 mg/dL before meals and less than 180 mg/dL 1 to 2 hours after the beginning of a meal.
What blood sugar level confirms diabetes?
To diagnose diabetes, your doctor will look at your HbA1c levels, which give a measurement of your blood sugar levels over time. An HbA1c level of 6.5% or higher on two separate tests means you have diabetes. An HbA1c between 5.7% and 6.4% means that you have prediabetes. Below 5.7% is considered normal.
How often should I check my blood sugar for type 2 diabetes?
Your doctor will tell you when it’s most important to check your blood sugar. It’s important to test when you have symptoms of high or low blood sugar. In general, it’s good to check when you first wake up, before and after meals, before and after exercise, and before you go to sleep.
What is the normal range for a blood sugar test?
A normal range for a fasting blood sugar test is 70 to 99 mg/dL. A non-fasting blood test will give variable results, depending on when you last ate, but should be below 125 mg/dL.
Are non-invasive blood sugar tests accurate?
Researchers are still honing methods for testing blood sugar that don’t involve getting a blood sample. These include passing a type of radiation into a part of the body with lots of veins, or analyzing sweat, saliva, tears, or urine. Developers are still working on accurate ways to do this. Data from blood is still the most reliable method today.
