Also known as: Ca, Urine.

Calcium 24-hour urine test requires two visits to the lab, one to pick up the specimen collection kit and one to return the specimen.  Patient is to void at 8 AM and discard the specimen. Then collect all urine including the final specimen voided at the end of the 24-hour collection period (ie, 8 AM the next morning).

Calcium is the most common and one of the most important minerals in the body. It is needed to build and fix bones and teeth, help nerves work, help blood clot, make muscles squeeze together, and help the heart to work. Most of the calcium in the body is stored in bone, the rest is found in the blood. The level of calcium in the blood is normally carefully controlled. When blood calcium levels get low (hypocalcemia), the bones will release calcium to bring it back to a good blood level. When blood calcium levels get high (hypercalcemia), the extra calcium will be stored in the bones or passed out of the body in urine and stool. High calcium levels in the urine may cause kidney stones.