AGAH-3-P0003 AGAH Poster presentation <p>Assessment of renal function from values of serum cystatin C concentration</p> Šrámek P psramek@pharmacon.cz Škopek J Reh C

Nemocnice Strahov Praha, Praha, Czech Republic

Pharmacon Research, Berlin, Germany

 AGAH <p>2004 Annual Meeting of the Arbeitsgemeinschaft für Angewandte Humanpharmakologie (Association for Applied Human Pharmacology)</p> 2004 3 p0003 Berlin, Germany, 29 February -2 March 2004 18 5 2004 28 5 2004

The aim of this study was to prove that serum cystatin C is a reliable marker of renal function and that it is a surrogate of creatinine in the estimation of the clearance capabilities of kidney. Knowledge of the creatinine clearance (CrCl) is important for the assessment of glomerular filtration rate (GFR), which is basis for dose adaptation during the treatment, for optimal dose selection in chemotherapy, for the control of renal graft function after transplantation, during clinical trials, etc. Most of the methods for assessment of GFR have its limitations and they bring a burden for a patient.

Serum cystatin C, a cysteine protease inhibitor,has been suggested as a new marker of glomerular filtrationrate (GFR). This study explored the possibility of replacingthe creatinine clearance (CrCl) as surrogate of GFR with cystatinC in early detection of renal impairment.

Methods

Serum creatinine and cystatin C concentrations as wellas 24-h CrCl were determined simultaneously in 37 subjects. Amongthem, 18 were healthy and 19 with different stage of renal disease.Creatinine was determined using a Jaffémethod. Serum cystatin C was determined by a particle-enhancedturbidimetric immunoassay.

Results

Cystatin C and creatinine correlated significantly when we compared all subjects (r = 0.77), the same correletion was between cystatin C and CrCl (r = -0.78). Close correlation was also found between cystatin C and creatinine resp. CrCl in patients (r = 0,66 /-0,71), but not in healthy subjects (r = 0,21/- 0,01). This fact could be explained by higher sensitivity of cystatine for renal function and its independence of the nutritional status of the organism (muscles mass, protein intake). We have calculated an equation for the conversion of serum value of cystatin C to CrCl (CrCl=33,4x1/cystatin C+21,1), from which we can assess a degree of renal function impairment.