A 72‐year‐old white female with end‐stage renal disease (ESRD) secondary to chronic glomerulonephritis has been on chronic hemodialysis for the past one and a half years. She has a history of congestive heart failure which has not been symptomatic since she began dialysis. She weighs 47 kg (103.4 lbs) and receives 3 hr of “conventional” hemodialysis with a blood flow rate of 350 ml/min which is well tolerated. Treatments are provided using a left upper arm polytetraflourethylene (PTFE) graft. Monthly percentage reduction in urea (PRU) values have been approximately 65%. However, her most recent PRU was 57% (predialysis blood urea nitrogen (BUN) 82 mg/dl, postdialysis BUN 35 mg/dl). Since her treatment parameters had not been changed, recirculation studies were obtained. The BUN values were: peripheral vein (P)—58 mg/dl, arterial line (A)—48 mg/dl, venous line (V)—23 mg/dl. Calculated recirculation was 29% ([P ‐ A]/[P ‐ V], 158 ‐ 48]/[58 ‐ 23]). The high level of recirculation prompted radiologic evaluation of the access. A fistulogram, including views of arterial inflow and central veins, showed no stenotic lesions. Needle placement was reviewed and found to be satisfactory. Repeat recirculation studies