MODEL RELEASED. Blood glucose testing. This machine uses a small blood sample to test a patient's blood sugar levels which are then displayed on the screen. The patient's finger is pricked to extract a drop of blood. The blood is placed on a chemically-coated silver strip and inserted into a glucometer, which gives a glucose reading. Diabetis mellitus is usually caused by insufficient insulin production by the pancreas. Treatment includes controlling dietary sugar intake and insulin injections.