Fig. 1

Non-linear regression analysis of FGF23 as a function of Cystatin C eGFR. Lines representing 20% above and 20% below the expected concentration are also shown. This curve can be described as Y = Span * e^-K*X + Plateau, where the half-life of the decay is 0.6932/K, Y is the expected FGF23 concentration, X is the eGFR and the curve begins at Span + Plateau and ends at Plateau. The values of the curve were: Span = 1295, K = 0.07247, Plateau = 38.35 and Halflife = 9.565