Journal of Human Sport and Exercise

Evaluation of equations for measuring eGFR based on serum creatinine and 6 cystatin C values in top level rugby players

Giuseppe Banfi, Gianluca Melegati, Gianvico Melzi d’Eril, Alessandra Barassi



Equations to estimate the glomerular filtration rate (GFR) have recently been advocated over serum creatinine values as a means to more accurately assess kidney function. The Cockcroft-Gault (CG) equation requires a body weight parameter, whereas the Modification of Diet in Renal Disease (MDRD) Study and Mayo Clinic Quadratic Equation (MCQE) formulae do not. We measured the serum creatinine and cystatin C concentrations in male athletes belonging to the Italian National Rugby team. Blood was obtained before the start of training and during competitive season. The serum creatinine level was measured by Jaffe and enzymatic reactions, cystatin C by nefelometry. The same parameters were measured in a control group of male, sedentary and overweight subjects. The concentrations of cystatin C were always into the reference ranges. The concentrations of creatinine were often higher than reference interval. The use of enzymatic method did not improve the specificity. The equations based on cystatin C and creatinine were not correlated. The two equations based on cystatin C were correlated. Two equations based on creatinine values were correlated (MDRD and MCQE); they were not correlated with CG. 29 level athletes, characterized from a high release of creatinine. The use of equations should be accurately evaluated: the CG equation can overestimate the eGFR, the MDRD and MCQE formulae systematically underestimates it. The use of equations to estimate GFR in the general population needs examination of their behaviour in subjects having atypical anthropomorphic characteristics.


Creatinine; Cystatin C; Rugby; Athletes; EGFR


Banfi, G., Del Fabbro, M., Lippi, G. Relation between serum creatinine and body mass index in elite athletes of different sport disciplines. Br J Sports Med. 2006; 40:675-8.

Banfi, G., Del Fabbro, M., Lippi, G. Serum creatinine concentrations and creatinine-based estimation of glomerular filtration rate in athletes. Sports Med. 2009; 39(4):331-7.

Banfi, G., Del Fabbro, M. Serum creatinine values in elite athletes competing in 8 different sports: comparison with sedentary people. Clin Chem. 2006; 52:330-1.

Banfi, G., Dolci, A. Preanalytical phase of sport biochemistry and haematology. J Sports Med Phys Fitness. 2003; 43(2):223-30

Bostom, A.G., Kronenberg, F., Ritz, E. Predictive performance of renal function equations for patients with chronic kidney disease and normal serum creatinine levels. J Am Soc Nephrol. 2002; 13:2140-4.

Burtis, C.A., Ashwood, E.R. Tietz textbook of clinical chemistry. Philadelphia: Saunders; 1994. Pp. 2184.

Ceriotti, G., Infusino, I., Luraschi, P., Panteghini, M. Evaluation of the trueness of serum creatinine measurement: results of a group of italian laboratories [in Italian]. Bioch Clin. 2007; 31:19-23.

Cockcroft, D.W., Gault, M.H. Prediction of creatinine clearance from serum creatinine. Nephron. 1976; 16:31-41.

Herget-Rosenthal, S., Bokenkamp, A., Hofmann, W. How to estimate GFR- serum creatinine, serum cystatin C or equations? Clin Biochem. 2007; 40:153-61.

Lamb, E.J., Tomson, C.R.V., Roderick, P.J. Estimating kidney functions in adults using formulae. Ann Clin Biochem. 2005; 42:321-45.

Levey, A.S., Greene, T., Kusek, J.W., Beck, G.L. A simplified equation to predict glomerular filtration rate from serum creatinine. J Am Soc Nephrol. 2000; 11(suppl): A0828.

Lippi, G., Banfi, G., Salvagno, G.L., Montagnana, M., Franchini, M., Guidi, G.C. Comparison of creatinine-based estimations of glomerular filtration rate in endurance athletes at rest. Clin Chem Lab Med. 2008; 46:235-9.

Lippi, G., Brocco, G., Franchini, M., Schena, F., Guidi, G.C. Comparison of serum creatinine, uric acid, albumin and glucose in male professional endurance athletes compared with healthy controls. Clin Chem Lab Med. 2004; 42:644-7.

Lippi, G., Salvagno, G.L., Montagnana, M., Schena, F., Ballestreri, F., Guidi, G.C. Influence of physical exercise and relationship with biochemical variables of NT-pro-brain natriuretic peptide and ischemia modified albumin. Clin Chim Acta. 2006; 367:175-80.

Macisaac, R.J., Tsalamandris, C., Thomas, M.C., Premaratne, E., Panagiotopoulos, S., Smith, T.J., et al. Estimating glomerular filtration rate in diabetes: a comparison of cystatin C and creatinine-based methods. Diabetologia. 2006; 49:1686-9.

Myers, G.L., Miller, W.G., Coresh, J., Fleming, J., Greenberg, N., Greene, T., et al. Recommendations for improving serum creatinine measurement: a report from the Laboratory Working Group of the National Kidney Disease Education Program. Clin Chem. 2006; 52:5-18.

Perkins, B.A., Nelson, R.G., Ostrander, B.E., Blouch, K.L., Krolewski, A.S., Myers, B.D., et al. Detection of renal function decline in patients with diabetes and normal or elevated GFR by serial measurements of serum cystatin C concentration: results of a 4-year follow-up study. J Am Soc Nephrol. 2005; 16:1404-12.

Perrone, R.D., Madias, N.E., Levey, A.S. Serum creatinine as an index of renal function: new insights into old concepts. Clin Chem. 1992; 38:1933-53.

Rule, A.D., Gussak, H.M., Pond, G.R., Bergstrahl, E.J., Steagall, M.D., Cosio, F.G., et al. Measured and estimated GFR in healthy potential kidney donors. Am J Kidney Dis. 2004; 43:112-9.

Rule, A.D., Larson, T.S., Bergstrahl, E.J., Slezak, J.M., Jacobsen, S.J., Cosio, F.G. Using serum creatinine to estimate glomerular filtration rate: accuracy in good health and in chronic kidney disease. Ann Intern Med. 2004; 141:929-37.

Rustad, P., Felding, P., Franzson, L., Kairisto, V., Lahti, A., Martensson, A., et al. The Nordic Reference Interval Project 2000: recommended reference intervals for 25 common biochemical properties. Scand J Clin Lab Invest. 2004; 64:271-84.

The Australasian Creatinine Consensus Working Group. Chronic kidney disease and automatic reporting of estimated glomerular filtration rate: a position statement. Med J Austr. 2005; 183:138-41.

Verhave, J.C., Fesler, P., Ribstein, J., Du Cailar, G., Mimran, A. Estimation of renal function in subjects with normal serum creatinine levels: influence of age and body mass index. Am J Kidney Dis. 2005; 46:233-41.

Vervoort, G., Willems, H.L., Wetzels, J.F. Assessment of glomerular filtration rate in healthy subjects and normoalbuminuric diabetic patients: validity of a new (MDRD) prediction equation. Nephrol Dial Transplant. 2002; 17:1909-13.

Wyss, M., Kaddurah-Daouk, R. Creatine and creatinine metabolism. Physiol Rev. 2000; 80:1108-1182.


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