Measurement of renal function in kidney donors using serum cystatin C and beta(2)-microglobulin.
BACKGROUND
The usefulness of serum cystatin C and serum beta(2)-microglobulin (B2M) as markers of glomerular filtration rate (GFR) were compared in kidney donors before and after nephrectomy.


METHODS
Blood samples were taken from 28 donors (15 women and 13 men) for serum creatinine, urea, cystatin C and B2M estimation a median of 7 days before and 10 days after nephrectomy.


RESULTS
Estimated GFR decreased from a median of 86.2 mL/min/1.73 m(2) to 60.3 mL/min/1.73 m(2), a median decrease of 28.6%. Serum creatinine increased by 40% and urea by 30.4%; serum cystatin C increased by 31.2% and serum B2M increased by 65.6%. Using published data on biological variation, critical values were calculated. An increase in serum creatinine above 18 micro mol/L detected the decline in renal function in 26/28 (92.9%) subjects. Increases in serum B2M greater than a critical value of 0.94 mg/L detected 24/28 (85.7%) of these subjects, but the critical value of 0.59 mg/L for cystatin C detected only 8/28 (28.6%).


CONCLUSIONS
Using critical values, serial measurement of serum creatinine was better than serum B2M in detecting reduced renal function. Because of its large intraindividual variation, serial serum cystatin C estimation was very poor in detecting reduced renal function.
John
George T
GT
Department of Nephrology, Christian Medical College and Hospital, Vellore 632 004, Tamil Nadu, India.
Fleming
Jude Joseph
JJ
Talaulikar
Girish S
GS
Selvakumar
R
R
Thomas
Paaulose P
PP
Jacob
Chakko K
CK
D000328:Adult; D015415:Biomarkers / Q000097:blood; D055316:Cystatin C; D015891:Cystatins / Q000097:blood*; D005260:Female; D005919:Glomerular Filtration Rate / Q000502:physiology; D006801:Humans; D007668:Kidney / Q000502:physiology*; D007674:Kidney Diseases / Q000175:diagnosis*; D007677:Kidney Function Tests; D019520:Living Donors; D008297:Male; D008875:Middle Aged; D001613:beta 2-Microglobulin / Q000097:blood*
D015415:Biomarkers; C525030:CST3 protein, human; D055316:Cystatin C; D015891:Cystatins; D001613:beta 2-Microglobulin