Cystatin C assay for the detection of renal dysfunction in Chinese renal transplant recipients.

Abstract Background : Accurate and rapid assessment of kidney function in patients after renal transplantation is of major significance. We investigated whether cystatin C can accurately reflect creatinine clearance over the entire range of kidney graft function. The performance of serum cystatin C as a screening marker of reduced creatinine clearance in renal transplantation was evaluated and compared to serum creatinine. Methods : Serum cystatin C, serum creatinine and creatinine clearance were measured in 103 adult renal transplant recipients. The cystatin C assay was performed using particle-enhanced immunonephelometry. Results : We demonstrated a significant linear correlation between 1/cystatin C and creatinine clearance over the entire range of transplant function, comparable to that of creatinine. Cystatin C detected reduced creatinine clearance with higher sensitivity of 92.9% (95% CI 80.5–98.4%) than serum creatinine, 71.4% (95% CI 55.4–84.3%). From the receiver operating characteristic (ROC) plots, serum cystatin C is superior to serum creatinine at 90% and 95% sensitivity. Conclusions : Serum cystatin C accurately reflects creatinine clearance over the entire range of transplant kidney function and is more efficacious than serum creatinine to detect reduced creatinine clearance in renal transplant recipients.