title: Conditions affecting the colorimetry of orotic acid and orotidine in urine.
abstract: We studied conditions affecting a colorimetric assay of total orotic acid (orotic acid plus orotidine) in urine. Most interfering substances can be conveniently removed on a small column of cation-exchange resin, and an improved control reaction corrects for residual background color. Analytical recovery from urine is nearly complete (greater than 95%) and the absorption spectrum for analyte eluted from the column closely resembles that for an orotic acid standard. We determined reference intervals for total orotic acid, expressed as a molar ratio to creatinine, for neonates, children, and adults, and assessed the effect of age, protein intake, and pregnancy. The method is simple enough to use as a reliable and accurate urine-screening test.
mesh_terms: D000328:Adult; D000367:Age Factors; D002648:Child; D002675:Child, Preschool; D003124:Colorimetry / Q000379:methods; D003404:Creatinine / Q000652:urine; D005260:Female; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D009963:Orotic Acid / Q000652:urine*; D014529:Uridine / Q000031:analogs & derivatives* / Q000652:urine
chemical_list: D009963:Orotic Acid; D003404:Creatinine; C008714:orotidine; D014529:Uridine