Osteoporosis Urine Mineral Screen

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:

rep-osteourine.pdf (Click to Download)

Sample Requirements:

Urine sample (second void EMU)

Postal Samples Acceptable:

Yes

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.