Measuring sugar levels in blood and urine yourself

You can measure your blood sugar levels yourself using an electronic device called a blood glucose meter. To do this, you prick your fingertip with a small needle, and place a drop of blood on a test strip. The strip is inserted into the blood glucose meter. The digital display shows your blood sugar level shortly afterwards. This is how the blood glucose meter is used:

• First of all, lay out everything you need: a blood glucose meter, a blood-sampling device with a sharp tip (lancet), and a test strip.
• Wash your hands before measuring your blood sugar because dirt can distort the results.
• Take a test strip out of the package and insert it into the glucose meter.
• Gently prick your fingertip with the lancet. If you prick the side of your fingertip, you feel it less. You can get the right amount of blood by gently squeezing the tip of your finger. It should just fill the test field of the strip.
• Then carefully place the drop of blood on the test strip without smearing it.
• After a short while, your blood sugar level will be displayed on the meter. Modern devices can save the measurements along with the date and time, and this information can be transferred to a computer or smartphone. If this is not possible, you could write the measurements down in a special diary or app, for instance.

If you measure your blood sugar levels frequently, pricking yourself is less uncomfortable if you use a different finger, or a different place on your finger, each time.

It can be helpful to read up about the various available devices and how to use them properly before getting a new glucose meter. It is important to make sure that you will be able to use the device easily in daily life.

It is completely normal for blood sugar levels to go up and down a little. This also happens in people who don't have diabetes. Blood sugar levels are influenced by things like what – and how much – we eat and drink, how much we exercise, and what medications we take. Depending on whether blood sugar levels are measured on an empty stomach or immediately after a meal, they vary between 3.3 to 7.8 mmol/L (about 60 to 140 mg/dL) in people who don't have diabetes. As shown in the following illustration, there are no clear-cut boundaries between the normal range of blood sugar and high or low blood sugar.

It is also possible to measure your sugar levels in your urine on your own. Having sugar in your urine is normally a sign of very high blood sugar levels. The extra sugar in the bloodstream is usually only removed by the kidneys at blood sugar concentrations of 10 mmol/L (180 mg/dL) and above. 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 best time of day to do the urine test, and whether to do it before or after eating. When measuring sugar in your urine yourself, you need a sample of urine that hasn’t been in your bladder for long. So an early-morning urine sample isn’t suitable because it has collected in your bladder overnight. Instead, it’s more typical to collect the sample when you go to the toilet the second time that day – about an hour after the first time. The test strip is then dipped into the sample. After about two minutes, the color pads on the test strip show the results.

To find out what the results mean, the colors on the test strip are compared with the color chart on the package. If the colors on the test strip don't change, you don't have sugar in your urine. The more the color changes, the more sugar there is in the urine, and therefore in the blood. But urine tests can't be used to monitor the effectiveness of diabetes medication over time because they can't measure your exact blood sugar levels. They can only determine whether you have very high blood sugar. This is because the body doesn’t generally get rid of sugar in urine if someone’s blood sugar levels are normal or slightly too high. If there is sugar in your urine, you should make an appointment to see a doctor about it.

Blood sugar levels can be measured more accurately by taking a blood sample from a vein and having it tested in a laboratory. Blood sugar is often measured as part of a routine blood test in hospital or at the doctor’s. A special kind of test called a glucose tolerance test also involves taking blood samples – in this case, to see how the body deals with larger amounts of sugar. The test involves drinking a very sugary solution beforehand.

Most people with diabetes have the HbA1c levels in their blood measured regularly. Your HbA1c value is a measure of how high your blood sugar levels have been on average over the last two to three months. This is an indication of how well-controlled your blood sugar is and whether your diabetes treatment might need to be adjusted.

You can also monitor your sugar levels using a device that measures the amount of sugar in fat tissue underneath your skin. This is called continuous glucose monitoring (CGM). CGM devices measure the sugar levels in the tissue fluid (interstitial fluid) every few minutes, and alert you if your blood sugar is too high or too low. CGM devices are also available in combination with an insulin pump. People who have type 2 diabetes generally only use them if it's not possible to monitor their blood sugar properly using other approaches.