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.
  • On a meter that needs a code from the test strips, 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 that came with the meter. All blood glucose meters have detailed
    instructions for performing the test. Follow these directions
    exactly.

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 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 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. But the finger is usually the most accurate place to test blood sugar.
  • 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.

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 rangesfootnote 1
For nonpregnant adults with diabetes
  • 80
    mg/dL (4.4 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.
  • 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 (2017). Standards of medical care in diabetes-2017. Diabetes Care, 40(Suppl 1): S1-S135. https://care.diabetesjournals.org/content/40/Supplement_1. Accessed December 15, 2016.

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

ByHealthwise Staff
Primary Medical Reviewer E. Gregory Thompson, MD – Internal Medicine
Kathleen Romito, MD – Family Medicine
Adam Husney, MD – Family Medicine
Specialist Medical Reviewer Alan C. Dalkin, MD – Endocrinology

Current as ofMarch 13, 2017