Clinical Performance Comparison of 2 THERANOVA 400 Dialyzer Prototypes in HD With High-Flux Dialyzers in HD and hv HDF Mode

Inclusion Criteria: 1. Patient has end-stage renal disease (Chronic kidney disease stage 5D) 2. Patient is 18 years of age or older 3. Patient is male or female 4. Patient, if female, is non-pregnant; and if capable of becoming pregnant, will be using a medically acceptable means of contraception during participation in the study 5 .Patient has been receiving HD or HDF therapy for \>3 months prior to study enrollment and is expected to survive for at least 12 months after enrollment. 6\. Patient has a stable functioning native fistula 7. Patient is willing to comply with the study requirements for therapy during the entire study treatment period 8. Patient is capable fo providing written informed consent to participate in the study Exclusion Criteria: 1. Patient is undergoing single-needle dialysis 2. Patient has an known abnormal k/λ ratio (less than 0.37, or greater than 3.1) 3. Patient has a known active infection and is currently receiving antibiotic treatment 4. Patient has known active cancer 5. Patient has a known positive serology test for human immunodeficiency virus (HIV) or hepatitis B,C or E 6. Patient has a known serious hemostasis disorder 7. Patient has a known monoclonal gammopathy 8. Patient has a known polyclonal gammopathy 9. Patient has a unstable condition as judged by the treating physician based on medical history, physical examination and laboratory testing including (but not limited to) any of the following: * Myocardial infarction within the last 3 months * Tachyarrhythmia or bradyarrhythmia absoluta * Unstable angina pectoris * Left ventricular ejection fraction \<30% * Significant pericardial disease 10. Patient has any other known comorbidity that could, in the opinion of the Investigator, potentially conflict with the study purpose or procedure 11. Patient has a known significant psychiatric disorder or mental disability that could interfere with the patient's ability to provide informed consent and/or comply with protocol procedures 12. Patient has a history of non-compliance with the dialysis prescription, as assessed by the Investigator 13. Patient has participated in another interventional clinical study in the past 3 months, or is currently participating in another interventional clinical study