This observational study will evaluate bioimpedance spectroscopy (BIS) measurements from patients undergoing hemodialysis.

This observational study will evaluate bioimpedance spectroscopy (BIS) measurements from patients undergoing hemodialysis. If changes in BIS parameters correlate with changes in fluid volume and patient symptoms, BIS may help provide a non-invasive way to estimate the amount of fluid to dialyze during a hemodialysis session. Data from this study may be used to inform the design of a future interventional trial of BIS use in hemodialysis patients.

Inclusion Criteria:

1. Age >=18 years of age;
2. End-stage renal disease with a GFR <15 mL/min/1.73m^2 and dialysis dependent requiring 3-times weekly dialysis;
3. Able and willing to remove shoes and stand on SOZO for BIS measurements;
4. Able to provide written informed consent and authorization to use and disclose health information.

Exclusion Criteria:

1. Is enrolled in a concurrent interventional study of an experimental treatment that may confound the results of this study, in the investigator's opinion;
2. Has a clinical condition that would not allow them to complete the study;
3. Is pregnant or planning to become pregnant; women of childbearing potential (or premenopausal) must be on 2 forms of contraception;
4. Is lactating;
5. Has an implanted cardiac rhythm management device (pacemaker or implantable cardioverter defibrillator);
6. Has an amputation of a limb/s resulting in them being unable to make contact with the SOZO electrodes (amputations of fingers and toes are not an exclusion);
7. Patient determined by the attending physician unlikely to be compliant with study procedures.

Adults (aged 18+ years) with end-stage renal disease, are known to a study investigator, and undergo hemodialysis 3-times per week at an outpatient dialysis unit.