Specimen Collection Manual and Test Catalog

5 mL aliquot of urine; minimum 1 mL.

Specimen may be collected without acid. Estimate total collection volume from 24-hour urine container. Add 30 mL 6N HCl to the 24-hour collection container and mix well prior to removing aliquot. 
Aliquot should not be removed unless acidified. If acid cannot be added to the 24-hour container, the 24-hour container can be transported to other hospital laboratories where urine can be acidified.

If an aliquot is received without the added acid, follow the processing step for Calcium, random urine.

Refrigerated (preferred). Room temperature or frozen specimen also acceptable.

Room temperature: 2 days. Refrigerated: 4 days. Frozen: 3 weeks.

Stability limits exceeded.

Urine calcium: 0.05-0.30 gm/24 hours.

Calcium - 24-hour urine, 24-hour total volume.

CA24

Urinary calcium reflects dietary intake, rate of calcium absorption by the intestine, and bone resorption. Urinary calcium is used primarily to evaluate parathyroid function and the effects of vitamin D.