title: Modification of estimation of the urinary ion-activity products of calcium oxalate and calcium phosphate.
abstract: Tiselius proposed simplified estimates of the ion-activity products of calcium oxalate, calcium phosphate, and brushite as the AP(CaOx) index, the AP(CaP) index, and the AP(Bru) index, respectively, which allowed assessment of the urinary saturation levels of these lithogenic substances. A number of urinary variables (calcium, magnesium, oxalate, phosphate, citrate, urine volume, and pH) are necessary to derive these indices. In addition, these three indices have correction factors corresponding to the urinary collection periods, although these periods were originally quite limited. In this study, the factors were shown to vary as a function of time. Therefore, they were incorporated into these indices after proper calculation so as to be usable for any collection period less than 24 hours. This means that the factors will now prove more useful in evaluating the urinary saturation levels after short-term collections.
authors.affiliation: Department of Urology, School of Medicine, Juntendo University.
authors.forename: Y
authors.initials: Y
authors.lastname: Ogawa
mesh_terms: D002129:Calcium Oxalate / Q000378:metabolism*; D002130:Calcium Phosphates / Q000378:metabolism*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D014545:Urinary Calculi / Q000737:chemistry / Q000652:urine; D014556:Urine / Q000737:chemistry*
chemical_list: D002130:Calcium Phosphates; C485828:alpha-tricalcium phosphate; C485830:tetracalcium phosphate; D002129:Calcium Oxalate; C485838:calcium phosphate, monobasic, anhydrous; C020243:calcium phosphate; C485829:calcium phosphate, dibasic, anhydrous; C494366:calcium phosphate, dibasic, dihydrate