title: Intra-individual variation in fasting urinary calcium- and hydroxyproline-creatinine ratios measured in metabolic bone clinic patients as both outpatients and inpatients.
abstract: The total intra-individual variation of fasting urinary calcium- and hydroxyproline-creatinine ratios were determined both as outpatients and as inpatients in 46 patients with metabolic bone disorders, including 20 women with osteoporosis. The intra-individual variation of both measurements was reduced considerably by collecting samples in the ward rather than in the outpatient setting, although this was not the case for a sub-group of osteoporotic women. The large intra-individual variation observed for calcium and hydroxyproline (30-40% in osteoporotic women) can give rise to misclassification in screening for fast bone losers. The very large critical difference required (109% and 94%, respectively, for calcium and hydroxyproline) for two results to reflect a significant change, is a major limitation in the use of these analytes for monitoring bone resorption in menopausal and osteoporotic women.
authors.affiliation: WHO Collaborating Centre for Metabolic Bone Disease, University of Sheffield Medical School, UK.
authors.forename: S D
authors.initials: SD
authors.lastname: Vasikaran
authors.forename: E V
authors.initials: EV
authors.lastname: McCloskey
authors.forename: S
authors.initials: S
authors.lastname: Kahn
authors.forename: J A
authors.initials: JA
authors.lastname: Kanis
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001851:Bone Diseases, Metabolic / Q000652:urine*; D002118:Calcium / Q000652:urine*; D003404:Creatinine / Q000652:urine*; D005215:Fasting; D005260:Female; D006801:Humans; D006909:Hydroxyproline / Q000652:urine*; D007297:Inpatients; D008297:Male; D008875:Middle Aged; D010045:Outpatients; D015203:Reproducibility of Results
chemical_list: D003404:Creatinine; D006909:Hydroxyproline; D002118:Calcium