Occasionally, the amount of blood required for the examination can't be extracted. We will be happy to send you a new blood collection kit. Tips for blood collection: You may want to keep your hand under warm water for a little longer and circle it longer. In addition, our customers tell us that the blood collection from the middle finger of the left hand works best. A successful blood collection may depend on your daily form. A low blood pressure can worsen the blood draw. Do not take your blood sample in the morning. It is better to wait until your circulation has really going". Try to place the lancets diagonally to your finger so that as much tissue as possible is "injured" and accordingly more blood escapes. In addition, you can easily retract the skin of the finger after the puncture so that the wound still opens a little. Drinking a lot is healthy! And supports a successful blood draw! Drink 1.5 - 2 litres of water the day before.If you need a new test kit, please contact us (help@cerascreen.com). We will then send you a new one free of charge.