title: Serum cystatin C as an index of renal function in kidney transplant patients.
abstract: Management of renal transplant patients requires periodic measurement of renal function, which is usually assessed by measuring the glomerular filtration rate (GFR). The most commonly used marker for GFR is serum creatinine, although muscle wasting and tubular secretion may lead to overestimation of the actual GFR. Serum concentrations of the low-molecular-weight proteins, cystatin C and beta(2)-microglobulin (B(2)M), may afford useful markers to determine a reduced GFR. We investigated whether these molecules provide reliable indicators of renal function in 75 renal transplant patients. Cystatin C and B(2)M correlated significantly with creatinine (r =.648, P <.05 and r =.578, P <.05, respectively). Inverse serum creatinine was superior to inverse cystatin C and inverse B(2)M when renal function equations were used (r =.95, P <.05, according to MDRD; r =.87, P <.05, according to Cockroft-Gault). Receiver operating characteristic (ROC) analysis was performed to quantitate the accuracy of the different markers to detect reduced GFR using a cutoff value of 70 mL/min. No significant difference between the areas under the ROC curves comparing cystatin C and B(2)M was observed; however, serum creatinine demonstrated a significantly greater value than cystatin C (.981 vs.724, P =.001). We conclude that serum creatinine is a more efficacious marker than serum cystatin C to assess renal function.
authors.affiliation: Central Laboratory, Akdeniz University Faculty of Medicine, Antalya, Turkey. halideakbas@akdeniz.edu.tr
authors.forename: S H
authors.initials: SH
authors.lastname: Akbas
authors.forename: A
authors.initials: A
authors.lastname: Yavuz
authors.forename: M
authors.initials: M
authors.lastname: Tuncer
authors.forename: C
authors.initials: C
authors.lastname: Ruhi
authors.forename: A
authors.initials: A
authors.lastname: Gurkan
authors.forename: R
authors.initials: R
authors.lastname: Cetinkaya
authors.forename: A
authors.initials: A
authors.lastname: Demirbas
authors.forename: M
authors.initials: M
authors.lastname: Gultekin
authors.forename: M
authors.initials: M
authors.lastname: Akaydin
authors.forename: F
authors.initials: F
authors.lastname: Ersoy
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000097:blood; D003404:Creatinine / Q000097:blood / Q000378:metabolism; D055316:Cystatin C; D015891:Cystatins / Q000097:blood*; D005919:Glomerular Filtration Rate / Q000502:physiology*; D006801:Humans; D016030:Kidney Transplantation / Q000502:physiology*; D012372:ROC Curve; D015203:Reproducibility of Results; D018709:Statistics, Nonparametric
chemical_list: D015415:Biomarkers; C525030:CST3 protein, human; D055316:Cystatin C; D015891:Cystatins; D003404:Creatinine