Study of How the Dose of Dialysis is Affected by Dialysate Flow Rate

Inclusion Criteria: * Adult subject ≥18 years of age undergoing chronic hemodialysis for end- stage renal disease (ESRD) three times a week for at least three months with a stable treatment prescription * Subject has no hospitalizations in previous three months for a significant illness related to a renal or dialysis problem except for vascular access surgery * Subject with an AV fistula or graft capable of routinely delivering a blood flow rate of 400 mL/min Exclusion Criteria: * Subject who is non-compliant with dialysis prescription * Subject whose hemodialysis schedule is not three times a week * Subject using a catheter for blood access * Subject who is not anticoagulated with heparin during hemodialysis * Subject with a current malignancy involving sites other than skin * Subject with a history of drug or alcohol abuse within the last six months * Subject who is believed to be unable to complete the entire study (e.g., due to a concurrent disease, life expectancy of less than a year, or scheduled kidney transplant * Subject who is pregnant * Subject who is considered incompetent to give an informed consent * Subject with a positive test for hepatitis B surface antigen within the past 30 days (testing for hepatitis B surface antigen is not required for subjects who have tested positive for hepatitis B antibody within the past year and any such patients will not be subject to this exclusion criterion) * Subject with known HIV infection (if this is not known, no HIV testing will be performed