Razi Journal of Medical Sciences

   Background &Aim: Early detection of decreasing glomerular filtration rate (GFR) is critical to prevent graft rejection in post-transplantation period. Serum creatinine has several drawbacks as a marker of GFR, so serum cystatin C has been proposed as an alternative GFR marker. Thus, we prospectively evaluated the diagnostic value of cystatin C measurements compared with serum creatinine in the early postoperative phase.

  Patients and Method: In 78 renal recipients, serum creatinine and cystatin C were measured on the 3rd, 7th and 14th days of post-transplantation period. GFR was established by creatinine clearance with the cut-off point of 80 ml/min/1. 73 m². The correlation between serum creatinine and cystatin C with GFR was determined. Sensitivity and specificity of these markers were analyzed by ROC procedures.

  Results: There were 78 renal recipients (51 males and 27 females) with the mean age of 34. 56± 13. 36 years and mean body mass index (BMI) of 22. 36± 3. 46 kg/m². Serum cystatin C was not influenced by gender, age and BMI. There was a significant correlation between serum creatinine and cystatin C levels with GFR on the 3rd, 7th, and 14th days (P< 0. 001). Analysis with ROC procedures showed a decrease in GFR (GFR< 80 ml/min/ 1. 73 m²) on the 7th day (P= 0. 023, AUC= 0. 694). Sensitivity and specificity of serum cystatin C were 67. 7% and 77. 9% respectively with the cut-off point of 2264 ng/ml.

  Conclusion: Cystatin C has good sensitivity to estimate the renal function in the early post-transplantation period, but its value as a marker of GFR is decreased at the end of the first week.