Cystatin C as a marker of glomerular filtration rate in voluntary kidney donors.
OBJECTIVE
Cystatin C is emerging as an endogenous marker of glomerular filtration rate. This study sought to assess the usefulness of serum cystatin C as a marker of glomerular filtration rate in comparison with serum creatinine and serum creatinine-based glomerular filtration rate estimations in voluntary kidney donors.


METHODS
Serum cystatin C and serum creatinine were estimated in 35 voluntary kidney donors. Glomerular filtration rate was estimated using: (1) Cockcroft-Gault method normalized to 1.73 m(2) of body surface area, (2) 4-variable Modification of Diet in Renal Diseases formula, and (3) (99m)Tc-DTPA double plasma sampling method. Glomerular filtration rate-double plasma sampling method was used as a reference value. Results were expressed as means ± SD.


RESULTS
The mean age of the participants was 44.23 ± 8.61 years old (19 women, 16 men). The mean serum creatinine was 0.83 ± 0.14 mg/dL, and the mean serum cystatin C was 0.71 ± 0.12 mg/L. Serum cystatin C showed significant correlation with serum creatinine (r = 0.864; P < .001). Glomerular filtration rate-MDRD showed the strongest correlation with glomerular filtration rate double plasma sampling method (r = 0.93; P < .001), followed by glomerular filtration rate-Cockcroft-Gault (r = 0.76; P < .001 ), serum creatinine (r = - 0.68; P < .001), and serum cystatin C (r = - 0.59; P < .001). The mean serum cystatin C values were 22.6% higher in men than in women. There was a significant correlation of serum cystatin C with glomerular filtration rate-Cockcroft-Gault (r = - 0.50; P = .002 ), glomerular filtration rate-MDRD (r = - 0.59; P < .001 ), and glomerular filtration rate-double plasma sampling method (r = - 0.59; P < .001 ).


CONCLUSIONS
Serum cystatin C is an optimal marker of glomerular filtration rate in voluntary kidney donors.
Department of Nephrology and Renal Transplantation, Sanjay Gandhi Post Graduate Institute of Medical Sciences, Lucknow, Uttar Pradesh, India. drjaisuresh@gmail.com
Krishnaswamy
K
Jaisuresh
Raj Kumar
RK
Sharma
Sonia
S
Mehrothra
Anupma
A
Kaul
Dharmendra Singh
DS
Badauria
Amit
A
Gupta
Narayan
N
Prasad
Apoorva
A
Jain
D000328:Adult; D015415:Biomarkers / Q000097:blood; D003404:Creatinine / Q000097:blood; D055316:Cystatin C / Q000097:blood*; D005260:Female; D005919:Glomerular Filtration Rate / Q000502:physiology*; D006801:Humans; D007668:Kidney / Q000502:physiology*; D007677:Kidney Function Tests; D016030:Kidney Transplantation; D019520:Living Donors; D008297:Male; D008875:Middle Aged; D016284:Technetium Tc 99m Pentetate
D015415:Biomarkers; D055316:Cystatin C; D003404:Creatinine; D016284:Technetium Tc 99m Pentetate