Abstract
In clinical practice,the glomerular filtration rate (GFR) is often estimated from serum creatinine (Scr).However,several recent studies have shown that serum cystatin C (SCysC) is a better parameter for the diagnosis of early impaired renal function than Scr.
In this study,we measured SCysC and 24 hour creatinine clearance (CLcr) levels in 102 in-hospital patients to determine if there was a relationship between the 2 parameters,finding that 1/SCysC was significantly positively correlated with CLcr.From the results,we derived the simple formula CLcr=65.45/SCysC-3.36(r=0.79,p<0.01).
Using a formula including the one above we predicted vancomycin concentrations based on SCysC and compared them with actual vancomycin concentrations in 17 patients.Our analysis of the results showed that the formula had greater prediction accuracy for vancomycin concentrations than the Cockcroft&Gault equation which is based on Scr.
These results suggest that SCysC is a better marker of renal function for setting initial doses of vancomycin and other drugs that are renally excreted.
