Indications:

Urine calcium can be used in the assessment of vitamin D status; if the serum vitamin 25-hydroxy cholecalciferol is > 200 nmol/L and the UCa/Cr is > 0.60, that is evidence for vitamin D toxicity. An increase in osteoclastic bone resorption will also raise the UCa/Cr. Vitamin D deficiency, or a calcium-restricted diet, may reduce the UCa/Cr ratio to < 0.25. Low sodium diets tend to decrease UCa/Cr, while a high sodium intake and excretion increases UCa/Cr.Urine phosphate is more influenced by diet than is urine calcium because of the greater proportion of dietary PO4 absorbed from the gut. High circulating vitamin D and PTH cause phosphaturia by increasing the renal clearance of phosphate.Phosphaturia also causes loss of magnesium in the urine. A low Mg value in an e.m.u. suggests magnesium deficiency, but a normal result does not exclude magnesium deficiency, which can be checked by measuring red cell magnesium.A wide reference interval for urine zinc reflects the poor intake of zinc in many subjects. Zinc is required for both osteoblastic and osteoclastic activity.

Patient Instructions:

Provide a second void early morning urine sample (I.e. a 20-30ml aliquot of urine from the second sample passed in a morning before you take any nutritional supplements).

Included in Profiles:

Osteoprosis profile

Sample Report:

Sample Requirements:

Urine sample (second void EMU)

Postal Samples:

References:

1. Endres DB, Rude RK. Mineral and bone metabolism. In: Burtis CA, Ashwood ER, Bruns DE. Tietz Textbook of Clinical Chemistry and Molecular Diagnostics 4th Ed. Elsevier-Saunder pubs, St. Louis Mis, 2006, pp 1891-1965. 2. Giannini S, Nobile M, Dalla Carbonare L, et al. Hypercalciuria is a common and important finding in postmenopausal women with osteoporosis. Eur J Endocrinol. 2003;149:209-213. 3. Nguyen TV, Eisman JA, Kelly PJ, et al. Risk factors for osteoporotic fractures in elderly men. Am J Epidemiol. 1996;144:255-263. 4. Ghazali S, Barratt TM. Urinary excretion of calcium and magnesium in children. Arch Dis Child. 1974;49:97-101.