Differences in the free Ca2+in undiluted urine from stone formers and normal subjects using a new generation of ion-selective electrodes
| Autor: | C.H. Fry, S.E.M. Langley |
|---|---|
| Rok vydání: | 1995 |
| Předmět: |
medicine.medical_specialty
Chromatography business.industry Urology Urinary tract stones Urine Hydrogen-Ion Concentration Sensitivity and Specificity Ion Ion selective electrode Surgery Spot urine Reference Values Electrode Humans Medicine Calcium Urinary Calculi Stone formers business Volunteer Ion-Selective Electrodes |
| Zdroj: | British Journal of Urology. 75:288-295 |
| ISSN: | 1464-410X 0007-1331 |
| Popis: | Objectives To measure the ionized Ca2+ in urine from normal subjects and patients with urinary tract stones. Patients and methods Urine samples were obtained from 37 normal subjects and 52 stone-formers. Ca2+ was measured using plastic dip-cast ion-selective electrodes; total Ca and other variables were measured by standard analytical techniques. Results The ionized Ca2+ and the total Ca were greater in stone-formers' urine although the difference was more significant with the Ca2+ data, especially at a standardized pH. Absolute values of the Ca2+ were dependent on the type of reference electrode used. The Ca2+ was a function of urine pH; lower values were recorded as pH increased. Measured values of the Ca2+ did not correlate well with calculated values using a standard computer program. Conclusions Measurement of the Ca2+ in spot urine samples at a standard pH provides a more discriminative test than total Ca for the presence of urinary tract stones. The pH dependence of the Ca2+ may have important consequences in the formation of urinary tract stones. The poor correlation between measured and computed values of Ca2+ emphasizes the importance of accurate measurement of this variable. |
| Databáze: | OpenAIRE |
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