Comparison of Serum Cystatin C and Creatinine Levels to Evaluate Early Renal Function after Kidney Transplantation

Accurate and rapid assessment of allograftfunction is essential in renal transplant recipients in order todetect allograft rejection and to monitor drug nephrotoxicity.we aimed to evaluate the usefulness of cystatin c as a markerof kidney allograft function in the early post-transplant periodand to compare this value with that of conventional serumcreatinine concentration.methods: twenty four patients scheduled for kidney transplantationat the kidney transplant center of ghaem hospital,mashhad, iran from september 2006 to november 2007,were sequentially enrolled into the present study. serumcreatinine and cystatin c concentrations and urine output weremeasured daily after transplantation for 3 weeks or until dischargefrom the hospital.results: on the 3rd postoperative day, with a cut-off value of75 ml/min for glomerular filtration rate, areas under the receiveroperating characteristic (roc) curves were 0.926 forcreatinine (p=0.021) and 0.815 for cystatin c (p=0.088). atthis point creatinine was more sensitive and specific than cystatinc in estimating glomerular filtration rate. on the 7th dayafter transplantation, areas under roc curves were 0. 893 forcreatinine (p=0.066) and 1.000 for cystatin c (p=0.017).therefore, cystatin c was more sensitive and specific thancreatinine in estimating glomerular filtration rate. in two patientswith acute rejection and arterial thrombosis, serum cystatinc concentrations increased earlier than serum creatinine.conclusion: there is a correlation between creatinine and cystatinc early after kidney transplantation. serum creatinine levelsseem to be more sensitive and specific for detecting transitorychanges in renal function in the 1st week after transplantation.after the 1st week after transplantation, cystatin c wasmore sensitive and specific than serum creatinine concentration.iran j med sci 2009; 34(2): 94-99.