Paradoxical Increase in Cystatin-c Levels in Conventional Hemodialysis

The conventional, low flux (LF) dialyser allows the removal of small molecular solutes like urea and creatinine. The removal of middle molecules (molecular weight between 500D and 60,000 D, which is nearly the size of albumin) is relatively low. Cystatin C has attractive characteristics as a representative middle molecule. Objective: To determine per dialysis Cys C reduction ratio (RR) in low flux group and to compare it with urea, marker of dialysis adequacy. Methods: Thirty seven patients were subjected to conventional, low flux dialysis. Serum urea and Cystatin C were measured pre and post dialysis. Cystatin C was measured by latex enhanced Immuno turbidimetry. Results: The URR is72.273±14.686% in low flux group & the Cys CRR is -9.7 ± 6.7 %. Discussion: The paradoxical increase in Cystatin C in the low flux group shows the ineffective clearance of middle molecules by low flux dialysers which is associated with dialysis related morbidity & mortality. Hence, Cys CRR could be applied as a surrogate marker for the inadequacy of dialysis.