Measuring correctly – what do I need to know?

Here are some general guidelines. Please read the instruction manual for your blood sugar meter for further details.


  • Gather together all the measuring equipment such as the blood sugar meter, test strips, lancing device and lancet, your diary and a pen.
  • If you take blood from your finger, wash your hands with soap and warm water before taking the blood sample. This is very important because glucose is excreted when you sweat, and this can affect the measured blood sugar values.
  • Sugar residues on the fingers could lead to excessively high blood sugar values. Warm water also helps the blood to flow, making it easier to get a drop of blood. Dry your hands thoroughly after washing.
  • Do not use disinfectant spray or alcohol. Under normal hygienic conditions neither is necessary and the values can be altered if residues are left on the skin.

Taking blood

  • Make sure that your fingertip is dry before obtaining the drop of blood. Otherwise the chemical reaction in the test area may be distorted, resulting in false values being measured.
  • By pricking at different depths using a lancing device you can obtain a drop of blood from the side of the fingertip easily and relatively painlessly.
  • Only press gently to get the drop of blood. Firm squeezing may cause the blood to be diluted with tissue fluid.
  • The most modern blood sugar measuring systems permit you to take blood from other parts of the body, such as your forearm, the ball of your hand, or your thumb, in order to protect your fingertips.

Applying the blood

The best way to apply the blood to the test strip depends on the measuring system being used. You should follow the instructions exactly. Some systems permit you to touch the test area with your finger. In this case smearing the blood has no effect on the measured result. Other systems react to this procedure by giving false blood sugar values.