The SFBC working group aimed to deal with biological tests outside the French nomenclature that may be useful for the follow-up of dialysis patients. Our discussion was divided into 3 parts: 1) evaluation of peritoneal membrane characteristics; 2) monitoring of renal replacement therapy using regional citrate anticoagulation; 3) estimation of residual renal function (RRF). International recommendations underline the importance of assessing peritoneal membrane characteristics for peritoneal dialysis prescription. This peritoneal equilibrium test requires the measurement in dialysate of the following parameters: glucose, urea, creatinine and sodium. As part of the monitoring of continuous renal replacement therapy using regional citrate anticoagulation, the determination of ionized calcium assay is essential according to national and international guidelines to ensure a balance between effective anticoagulation and appropriate calcium levels. Finally, the RRF plays a key role in the dialysis adequacy and patient survival. European and international recommendations highlight the potential interest of RRF in peritoneal dialysis and hemodialysis. The RRF corresponds to the mean of urinary urea and creatinine clearance, assessed from a urine collection with measurement of urinary urea.