A Comparison of the Tiselius Risk Index (RI) and Relative Saturation (RS) of Calcium Oxalate (CaOx) in Stone Formers
Recently a simplified estimation of the ion activity product for calcium (AP-CaOx) in urine has been described using a computer program1. Subsequently a metabolic risk index, RI, was developed which was posited to be proportional to AP-CaOx at the same urine volume (Fig. 1). The Tiselius Risk Index is given by: RI = (Ca/Cr) 0.71 x (Ox/Cr)/(Mg/Cr) 0.14 x (Cit/Cr) 0.10 where Ca = calcium, Ox = oxalate, Mg = magnesium, Cit = citrate (all in mmol/1), and Cr = creatinine (in mol/1).
KeywordsCalcium Intake Urine Volume Risk Index Calcium Oxalate Dietary Calcium Intake
Unable to display preview. Download preview PDF.