Advanced Medical Electronics (AME) and our partners propose a minimally-invasive system for continuous monitoring of potassium. Measurement of blood levels of potassium is important in clinical medicine. Abnormalities of potassium, common in heart and kidney disease, can be aggravated by many medications used to treat these disorders leading to arrhythmias and death. Determination of potassium values has always required access to blood - either by phlebotomy or other skin puncture. The proposed project involves developing a minimally invasive technology that permits determining potassium values without obtaining blood, by recording the body's own response to potassium levels, thereby increasing comfort and convenience for the patient. This technology can be applied in the hospital or at home, extending a remote monitoring platform, and promoting independence and wellness by permitting medication adjustments without hospitalization for frequent blood tests. The ability to manage patients remotely and thereby identify and address health issues early and without need for a clinical visit and blood draw improves care for patients and increases the economic efficiency of care delivery for payors and providers. A prototype system will be developed and evaluated in phase 1.