When detecting irregularities in the blood electrolytes (e.g., potassium or sodium), one would like to avoid invasive procedures if possible. With the new sensors, the measurement can be done in body sweat or saliva instead. The aim is to monitor the progress of the therapy at home or to carry out repetitive routine examinations without visiting the medical practice one day. The sensors for this purpose are manufactured cost-effectively using screen printing, and a special electronic system transmits the acquired data to the doctor's office via mobile communication.