GAMMA Study: Patient Self-testing of Capillary Blood Potassium: A Validation Study and Measurement Performance in Patients.

"Calibration Phase (1 visit) (Hemodialysis patients and subjects not on dialysis) Each patient will have one venous blood collection. Among them, one 30 patients one capillary sample is collected. In this phase, the HCP is the user of the device.~Comparison Phase~For subject not on dialysis (total 2 visits):~Each patient will have one venous blood collection per visit Each patient will be equipped with CardioRenal device and trained to do the self-test~For Hemodialysis patients (total 1 visit) :~Each patient will have one venous blood collection per visit Each patient will be equipped with CardioRenal device and trained to do the self-test"