Few studies have explored how patient characteristics may influence clearances. We sought to determine if patient age, sex, size, renal disease, blood pressure, hematocrit, serum total proteins and albumin affected peritoneal clearances, drainage volumes or dialysate protein concentration. We found inulin clearances to be related to surface area and total serum proteins. Creatinine clearance was related to age, serum albumin and hematocrit. Sex, blood pressure or type of renal disease did not influence peritoneal clearances.