Measuring blood sugar levels and sugar in urine

Many people with diabetes mellitus measure their blood sugar levels themselves. For those who inject insulin several times a day, checking their sugar level (glucose level) with a blood glucose meter is an important part of their daily treatment. The blood sugar level measured is one of the factors that determine how much insulin they inject at mealtimes. Other people with diabetes do not check their sugar levels as frequently or only have their doctor check them. We will now describe the different methods and explain how you can measure sugar levels in your blood and urine yourself.

You can find more detailed information on the different types of diabetes and their treatment options here. To read more about whether self-monitoring blood or urine sugar levels has benefits for people with diabetes who do not inject insulin, click here.

Measuring blood sugar levels yourself

You can measure your blood sugar levels yourself by using an electronic device. To do this you take a drop of blood from your finger using a pricker and place it onto a test strip. Then you put the strip into the blood glucose meter, and the device starts measuring. A short time after that the blood sugar level appears on the digital display. This is how you do the measurement:

• First, have all the materials ready that you need for the measurement, namely the blood glucose meter, a finger pricker with a fine needle (lancet) and a test strip.
• Dirt and other stains can mix with the blood and distort the measuring result. So it makes sense to wash your hands beforehand.
• Then take a test strip out of the package and put it into the glucose meter.
• If you prick the needle on one side of the fingertip, you do not feel it as much as on the pad.
• One small drop of blood already is enough for the measurement. It should just fill the test field. You can automatically get the right amount by carefully pressing the tip of your finger.
• Carefully place the drop of blood onto the test strip without smearing it. After a short while the glucose meter will display the blood sugar level. Some devices can store the measurements taken along with the date and time of the day, and transfer this information to a computer. If this is not possible it makes sense to write the measurements down in a special diary, for example.

If you frequently measure your blood sugar levels, pricking yourself will be less unpleasant if you do not always take the same finger but regularly change the one you use. Another option is to prick the tip of the same finger on a different place each time.

Different glucose meters are used differently. It helps to get information about the different types of device before you get a new one to make sure you get one you can handle in your everyday life.

What does the result mean?

It is completely normal for our blood sugar levels to go up and down a little. This also happens in healthy people every day. Blood sugar levels depend on the amount and type of food and drink we have, how much we exercise, and what medications we take. Depending on whether they have been fasting or just eaten, blood sugar levels in healthy people vary between about 60 and 140 milligram per deciliter (mg/dL) blood. This is about 3.3 to 7.8 millimoles per liter (mmol/L). As you can see on the graphic below, there are no clear-cut borders between the normal range of blood sugar and high and low blood sugar.

Measuring sugar in your urine yourself

Another test you can do yourself too is measuring the amount of sugar in your urine. Sugar in the urine generally is a sign of very high blood sugar levels. This is because our bodies usually only get rid of extra sugar in the blood via the kidneys too if blood sugar levels are as high as about 180 mg/dL or more. In order to measure the amount of sugar in your urine you need a urine test strip (dipstick) and a container for collecting urine.

It is important to talk with your doctor about the time of the day you should take the measurements and whether to do the test before or after eating. For measuring sugar in your urine yourself you need a fresh urine sample. This means that the urine was produced only a short time ago. You would not use morning urine, for example, which has collected in the bladder during the night. Instead you would typically take a urine sample half an hour or an hour after going to the toilet the last time. The test strip is then dipped into the container. After about two minutes, the color pads on the test strip show the result.

What does the result mean?

Compare the color changes on the test strip with the color chart on the package. If the pad on the test strip does not change color, there is no sugar in the urine. The more the color changes, the more sugar there is in the urine, and thus in the blood. The test does not give an exact result, however. It is important to know that a urine test cannot detect low blood sugar levels (hypoglycemia) because if blood sugar level is normal or low, normally no sugar is excreted in the urine.

To read comprehensive information on urine tests click here.

Measuring blood sugar levels in a laboratory

A laboratory can measure blood sugar levels a lot more exactly from a blood sample taken from a vein. Blood sugar is sometimes measured as part of a routine blood examination in the hospital or a doctor’s practice. If you do a glucose tolerance test, blood is also drawn to test the sugar levels.

Most people with diabetes have their HbA1c level in the blood measured regularly. The HbA1c value indicates how high the blood sugar level has been on average in the last 6 to 8 weeks. This can indicate how well controlled the blood sugar levels are and whether the diabetes treatment might need to be changed.

Author: Institute for Quality and Efficiency in Health Care (IQWiG)

© IQWiG (Institute for Quality and Efficiency in Health Care) Last update of this website: 05/22/2012