Aim from K@Home is to allow an everyday home monitoring of the potassium value by the development of potassium-test stripe, like with the diabetes patients who supervise their blood sugar level by measurements with glucose-test stripe from a drop of capillary blood from the finger berry and with it the emergencies and hospital admissions to reduce or to prevent. It is fact that haemolysis has a strong influence on the measured potassium concentration. It is likely that by using capillary blood a haemolysis appears and therefore distorted potassium concentrations are measured.