The communication deals with recommendation of the Working group for improving the quality measurement of serum creatinine created within the framework of National Kidney Disease Education Program (NKDEP) USA. The main problem of creatinine determination is lack of traceability of measurement results to reference method IDMS demonstrated by results of large interlaboratory comparison studies. Big problems with estimation of GFR consequently follow. The introduced working group proposes number of recommendations for the improvement of situation addressed to laboratories, IVD manufacturers and EQA organisers.

        Key words: traceability, bias, creatinine, GFR, recommendation.