The importance of metrological traceability on the validity of creatinine measurement as an index of renal function International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) IFCC Scientific Division, Working Group on Standardization of Glomerular Filtration Rate

The glomerular filtration rate (GFR) is currently considered the best overall index of kidney function. The possibility that laboratories might routinely report an estimated GFR has become practically feasible with the development of a formula, the ‘‘four-variable’’ This position paper was commissioned by IFCC, but it does not carry any official IFCC endorsement. IFCC Sections printed in J. Clin. Chem. Clin. Biochem. are 2) listed in the Cumulative Index, which appeared in connection with the contents of this journal in Volume 27, 1989 and since 1991 have been printed in (Eur.) J. Clin. Chem. Clin. Biochem. IFCC 1991/1 Vol. 29, 435–457 IFCC 1991/2 Vol. 29, 531–535 IFCC 1991/3 Vol. 29, 577–586 IFCC 1991/4 Vol. 29, 767–772 IFCC 1992/1 Vol. 30, 901–905 IFCC 1994/1 Vol. 32, 639–655 IFCC 1995/1 Vol. 33, 247–253 IFCC 1995/2 Vol. 33, 399–404 IFCC 1995/3 Vol. 33, 623–625 IFCC 1995/4 Vol. 33, 627–636 IFCC 1995/5 Vol. 33, 637–660 IFCC 1997/1 Vol. 35, 317–344 IFCC 1997/2 Vol. 35, 345–349 IFCC 1997/3 Vol. 35, 805–831 IFCC 1997/4 Vol. 35, 833–843 For IFCC sections printed in Clin. Chem. Lab. Med. since 1998, please visit the link http://degruyter.com/journals/ extenza, where they are freely accessible. *Corresponding author: Prof. Mauro Panteghini, Laboratorio Analisi Chimico-Cliniche, Ospedale Luigi Sacco, Via GB Grassi, 20157 Milano, Italy Phone: q39-02-39042806, Fax: q39-02-50319835, E-mail: [email protected] Modification of Diet in Renal Disease study (MDRD) equation that uses age, sex, race, and serum creatinine parameters. However, a limitation of this equation for general implementation in healthcare is related to the use of differently calibrated creatinine measurement procedures among laboratories. The only way to achieve universal implementation of the GFR prediction equation, with the associated clinical benefits for patients, is, therefore, to promote worldwide standardization of methods to determine creatinine, together with the introduction of a revised GFR-estimating equation appropriate for use with standardized creatinine methods. Clin Chem Lab Med 2006;44:1187–92.