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Home Blood Glucose Test

Test Overview

A home blood glucose test measures the amount of a type of sugar, called glucose, in your blood at the time of testing. The test can be done at home or anywhere, using a small portable machine called a blood glucose meter.

Home blood sugar testing can be used to monitor your blood sugar levels. Talk with your doctor about how often to check your blood sugar. How often you need to check it depends on your diabetes treatment, how well your diabetes is controlled, and your overall health. People who take insulin to control their diabetes may need to check their blood sugar level often. Testing blood sugar at home is often called home blood sugar monitoring or self-testing.

If you use insulin rarely or don't use it at all, blood sugar testing can be very helpful in learning how your body reacts to foods, illness, stress, exercise, medicines, and other activities. Testing before and after eating can help you adjust what you eat.

Some types of glucose meters can store hundreds of glucose readings. This allows you to review collected glucose readings over time and to predict glucose levels at certain times of the day. It also allows you to quickly spot any major changes in your glucose levels. Some of these systems also allow information to be saved to a computer so that it can be turned into a graph or another easily analyzed form.

Some newer models of home glucose meters can communicate with insulin pumps. Insulin pumps are machines that deliver insulin through the day. The meter helps to decide how much insulin you need to keep your blood sugar level in your target range.

Why It Is Done

A home blood glucose test is an accurate way to measure your blood sugar level at the time of testing. If you have diabetes, testing your blood glucose levels at home provides information about:

  • Your blood sugar level. It is important to know when your blood sugar is high or low, to prevent emergency situations from developing. It is also important to treat consistently high blood sugar levels so you can decrease your chances of developing heart, blood vessel, and nerve complications from diabetes.
  • How much insulin to take before each meal. If you take rapid-acting or short-acting insulin before meals, the blood sugar test results can help you determine how much insulin to take before each meal. If your blood sugar level is high, you may need extra insulin. If your blood sugar level is low, you may need to eat before you take any insulin.
  • How exercise, diet, stress, and being ill affect your blood sugar levels. Testing your blood sugar can help you learn how your body responds to these things. Where possible, you can adjust your lifestyle to improve your blood sugar level.

Home blood sugar testing also may be used to:

  • Decide on an initial insulin dose and schedule or to adjust the insulin doses or schedule.
  • Test blood sugar levels in people who have symptoms of high blood sugar (hyperglycemia) or low blood sugar (hypoglycemia).

How To Prepare

Equipment

You can buy home blood glucose testing equipment at a pharmacy and any grocery or discount store that has a pharmacy. You also may be able to buy the testing equipment and supplies through the mail or on the Internet.

The supplies you will need for testing blood glucose include:

  • A blood glucose meter.
  • Testing strips. These are made to be used with a specific model of meter.
  • Sugar control solution. Each meter requires a specific solution. Many new meters are made to operate without a control solution.
  • Short needles called lancets for pricking your skin.
  • A pen-sized holder for the lancet (lancet device), which positions the lancet and controls how deeply it goes into your skin.
  • Clean cotton balls. These are used to stop the bleeding from the testing site.

General instructions

To make sure you get accurate results when you test your blood sugar:

  • Check the expiration date on the bottle of testing strips. Do not use test strips that have expired. The test results may not be accurate.
  • Always store unused test strips in the container. Test strips that have been exposed to air may not give accurate results.
  • Match the code number on the testing strips bottle with the number on the meter. If the numbers do not match, follow the directions with the meter for changing the code number.
  • Follow the instructions with the meter. All blood glucose meters have detailed instructions for performing the test. Follow these directions exactly.
  • Check the accuracy of the meter's results. Use the sugar control solution made by the meter's manufacturer. Follow the directions that came with the meter for proper use of the control solution or compare the results with your latest lab values.

Talk to your doctor about any concerns you have regarding the need for the test, its risks, how it will be done, or what the results will mean. To help you understand the importance of this test, fill out the medical test information formmedical test information form(What is a PDF document?).

How It Is Done

A home blood sugar test involves pricking your finger, palm, or forearm with a small needle (lancet) to collect a drop of blood and placing the blood on a special test strip, which you insert into the blood glucose meter before you begin the test. The blood glucose meter displays the results of a blood sugar test within a minute after testing.

The instructions for testing are slightly different for each model of home blood glucose meter. For accurate results, follow the instructions for your meter carefully. When testing blood sugar using a home blood glucose meter:

  • Wash your hands with warm soapy water. Dry them well with a clean towel.
  • Insert a clean needle (lancet) into the lancet device. The lancet device is a pen-sized holder for the lancet. It holds, positions, and controls how deeply the lancet goes into the skin.
  • Remove a test strip from the bottle of testing strips. Replace the lid immediately after removing the strip to prevent moisture from affecting the other strips. Testing strips are sometimes stored inside the meter.
  • Prepare the blood sugar meter (glucose meter). Follow the instructions included with your meter.
  • Use the lancet device to stick the side of your fingertip with the lancet. Do not stick the tip of your finger; the stick will be more painful and you may not get enough blood to do the test accurately. Some new blood sugar meters use lancet devices that can obtain a blood sample from sites other than the fingers, such as the palm of the hand or the forearm.
  • Put a drop of blood on the correct spot of the test strip.
  • Using a clean cotton ball, apply pressure where you stuck your finger (or other site) to stop the bleeding.
  • Follow the directions with your blood sugar meter to get the results. Some meters take only a few seconds to give the results.
  • You can write down the results and the time that you tested your blood. But most meters will store results for many days or weeks, so you can always go back later and retrieve them. You and your doctor will use this record to see how often your blood sugar levels have been within the recommended range. Your doctor also will use the results to decide if a change in medicine (insulin or pills) for diabetes is needed.

Safely dispose of your lancets after using them. Do not throw them into the household trash. A used lancet might accidentally stick someone. Place used lancets into a plastic container, such as an empty detergent bottle. Seal the container when it is about three-quarters full. Check with your local trash disposal agency about the proper disposal of lancets. Some agencies have specific instructions for the disposal of medical waste. Sometimes your doctor's office will dispose of them for you.

How It Feels

Your fingertips may get sore from frequent pricking for blood sugar testing. To help prevent sore fingertips:

  • Always prick the side of your finger. Do not prick the tip of your finger. This increases the pain, and you may not get enough blood to do the test accurately. Also, do not prick your toes to get a blood sample. This can increase your risk of getting an infection in your foot.
  • Don't squeeze the tip of your finger. If you have trouble getting a drop of blood large enough to cover the test area of the strip, hang your hand down below your waist and count to 5. Then squeeze your finger, beginning close to your hand and moving outward toward the tip of your finger.
  • Use a different finger each time. Keep track of which finger you stick so that you don't use some fingers more than others. If a finger becomes sore, avoid using it to test your blood sugar for a few days.
  • Use a different device. If you are having trouble with sore fingers, you may want to try a meter that obtains a blood sample from sites other than the fingers, such as the palm of the hand or the forearm.

Risks

There is very little risk of complications from testing your blood with a home blood sugar monitor.

  • You may get an infection in your finger if you do not wash your hands before sticking your finger.
  • You may get hardened areas on your fingertips from frequent blood sugar testing. Use lotion to help soften these areas.

Results

A home blood glucose test measures the amount of a type of sugar, called glucose, in your blood at the time of testing. The test can be done at home or anywhere, using a small portable machine called a blood glucose meter.

The American Diabetes Association (ADA) recommends that you stay within the following blood sugar level ranges. But, depending on your health, you and your doctor may set a different range for you.

Recommended blood sugar level ranges1
For nonpregnant people with diabetes:
  • 70 mg/dL (3.9 mmol/L) to 130 mg/dL (7.2 mmol/L) before meals
  • Less than 180 mg/dL (10 mmol/L) 1–2 hours after the start of a meal
For women who have diabetes related to pregnancy (gestational diabetes):
  • 95 mg/dL (5.3 mmol/L) or less, before breakfast
  • 140 mg/dL (7.8 mmol/L) or less, 1 hour after the start of a meal, or 120 mg/dL (6.7 mmol/L) or less 2 hours after the start of a meal

 

Many conditions can change blood glucose levels. Your doctor will discuss any significant abnormal results with you in relation to your symptoms and past health.

What Affects the Test

Reasons you may not be able to have the test or why the results may not be helpful include:

  • Alcohol in the drop of blood. If you clean your skin with rubbing alcohol, let the area dry completely before sticking it with the lancet.
  • Water or soap on your finger.
  • Squeezing your fingertip.
  • A drop of blood that is either too large or too small.
  • Very low (below 40 mg/dL or 2.2 mmol/L) or very high (above 400 mg/dL or 22.2 mmol/L) blood sugar levels.
  • Humidity or a wet test strip. Do not store your test strips in the bathroom. When you remove a strip from the bottle, promptly secure the lid back on the bottle to prevent humidity from damaging the unused strips.

Proper care of the blood sugar testing equipment is important to ensure safety and to get accurate results.

  • Follow the manufacturer's instructions.
  • Do not drop or deliberately bump your meter.
  • Do not store your meter in a very hot or very cold place.
  • Clean your meter regularly, and change the batteries as instructed.

What To Think About

Equipment

  • There are several different styles of home blood glucose meters on the market today. Each meter has slightly different features. Look for a meter that fits your needs. You can also search the Internet for home glucose monitoring equipment.
  • Most insurance programs cover the cost of home blood glucose testing equipment. Find out if your insurance company requires a letter or prescription from your doctor for reimbursement purposes.

Results

  • If you think a test result from your meter is different from what you expected, repeat the test. You may also need to recalibrate your machine before you test again if the result is not what you expect. If you get similar results with the second test, you may need to talk with your doctor about what to do next.
  • You can write down the results and the time that you tested your blood. But most meters will store results for many days or weeks, so you can always go back later and retrieve them. This can help you and your doctor determine whether the steps you take to control your diabetes are working.
  • You can check the accuracy of your blood sugar meter when your blood sugar test is done at the doctor's office or lab. To do so, test your blood sugar using your blood glucose meter at the same time the lab test is done. If your meter is accurate, the results should be no more than 15% above or below the lab's results. Your doctor may suggest that you do this if your recorded home values do not match the results obtained in the doctor's office.
  • A urine test for sugar is not an accurate indication of blood glucose levels. Sugar levels in the blood can be high long before the sugar can be detected in the urine. But urine testing may be used to check for a serious condition called diabetic ketoacidosis. The blood can also be tested for ketones. To learn more, see the topic Ketones.

Monitoring

  • If you are using an insulin pump or if you use insulin more than once a day, you will need to test your blood sugar often. The number of times that you test may change every day, depending on when you eat, what you do, and how you feel. For example, you may need to test your blood sugar 5 times one day and 10 times the next day.
  • Routine prenatal visits and regular home blood glucose monitoring are very important for pregnant women with diabetes. Women who keep their blood glucose levels within a recommended range increase their chances of having healthier babies and decrease their chances of having diabetes-related complications.
  • Continuous glucose monitoring (CGM) can be helpful for people who use insulin to reach their target range. You will still need to check your blood sugar using the finger (or other site) prick method a few times a day to check if your monitor is reading properly. It can also help people who do not have symptoms when they have low blood sugar or who have low blood sugar often.

References

Citations

  1. American Diabetes Association (2013). Standards of medical care in diabetes—2013. Diabetes Care, 36(Suppl 1): S11–S66.

Other Works Consulted

  • Chernecky CC, Berger BJ (2013). Laboratory Tests and Diagnostic Procedures, 6th ed. St. Louis: Saunders.
  • Fischbach FT, Dunning MB III, eds. (2009). Manual of Laboratory and Diagnostic Tests, 8th ed. Philadelphia: Lippincott Williams and Wilkins.
  • Pagana KD, Pagana TJ (2010). Mosby’s Manual of Diagnostic and Laboratory Tests, 4th ed. St. Louis: Mosby.

Credits

By Healthwise Staff
Primary Medical Reviewer E. Gregory Thompson, MD - Internal Medicine
Specialist Medical Reviewer Alan C. Dalkin, MD - Endocrinology
Last Revised August 15, 2013

This information does not replace the advice of a doctor. Healthwise, Incorporated disclaims any warranty or liability for your use of this information. Your use of this information means that you agree to the Terms of Use. How this information was developed to help you make better health decisions.

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