Estimation of the glomerular filtration rate – comparison between serum creatinine, cystatin c and calculated creatinine clearance

oleh: Radovan Hojs, Sebastjan Bevc, Robert Ekart, Maksimiljan Gorenjak, Ludvik Puklavec

Format: Article
Diterbitkan: Slovenian Medical Association 2006-08-01

Deskripsi

<p><strong>Background:</strong> With increasing emphasis on the earlier detection and management of chronic kidney disease (CKD), estimation of the glomerular filtration rate (GFR) has assumed greater importance. GFR is often estimated from serum creatinine, recently also from serum cystatin C and by Cockcroft-Gault (C&amp;G) and Modification of diet in renal disease (MDRD) formulas. In our study different markers of GFR were compared with gold standard 51CrEDTA clearance.</p><p><strong>Patients and methods:</strong> We included 468 patients with CKD stages 2–5 (216 women and 252 men, average age 60.4 ± 14.3 years), who performed 51CrEDTA clearance. In each patient, serum creatinine and cystatin C were determined, creatinine clearance was calculated using C&amp;G and MDRD formulas.</p><p><strong>Results:</strong> We found significant correlation between 51CrEDTA clearance with serum creatinine (r = –0.889), reciprocal of serum creatinine (r = 0.866), serum cystatin C (r = –0.902), reciprocal of serum cystatin C (r = 0.901) and with calculated creatinine clearance from C&amp;G (r = 0.808) and MDRD formulas (r = 0.901). The ROC curve analysis (cut–off for GFR 60 ml/min/1.73m2) showed that serum cystatin C had higher diagnostic accuracy than serum creatinine (P = 0.006) and calculated creatinine clearance from C&amp;G formula (P = 0.004). No difference in diagnostic accuracy was found between serum cystatin C and creatinine clearance calculated from the MDRD formula.</p><p><strong>Conclusions:</strong> Serum cystatin C is a better marker of GFR and has a higher diagnostic accuracy than serum creatinine and calculated creatinine clearance from C&amp;G formula. No difference in diagnostic accuracy was found between serum cystatin C and creatinine clearance calculated from the MDRD formula.</p>