The investigation is a prospective cohort study, where two patient groups will be monitored by a wearable bioimpedance sensor during their scheduled treatment. The overall objective is to assess the bioimpedance sensor's ability to detect local and systemic fluid accumulation.

Sub-investigation A will investigate the ability of the device to detect fluid accumulation in patients with stable chronic kidney disease undergoing regular and planned hemodialysis.

Sub-investigation B will investigate the ability of the device to track hydration status in patients scheduled for an "intensive" dialysis treatment regime, due to severe overhydration.

In Sub-investigation A, patients will be monitored for at least 10 consecutive dialysis sessions, and for a minimum of 3 weeks. Patients will wear two sensors (upper back and lower anterior leg).

In Sub-investigation B, patients will use the device throughout their whole treatment period, and for most patients, this will correspond to 2-6 dialysis treatments over 3 to 10 days. Patients will wear four patches (upper back, lateral thorax, anterior thigh, and lower anterior leg).

Inclusion Criteria:

• Age ≥ 18 years
• Regular hemodialysis (≥ 2 times weekly) with ultrafiltration volume ≥ 1 liter (Sub-investigation A)
• Scheduled for intensive dialysis treatment due to severe overhydration (Sub-investigation B)

Exclusion Criteria:

• Known allergies or skin sensitivities to electrode hydrogel and/or acrylic adhesives
• Implantable pulse generators such as pacemakers and defibrillators, and/or use of other electrical medical equipment for which an interaction effect with the investigational device cannot be ruled out.
• Patients undergoing MRI
• Breached skin at patch mounting area
• Pregnancy
• Any medical or psychiatric condition, which in the opinion of the investigator precludes participation