Calcium (Ca) in Urine
A test for
calcium in urine is a 24-hour test that checks the
amount of calcium that is passed from the body in the urine. Calcium is the most common
mineral in the body and one of the most important. The body needs it to build
and fix bones and teeth, help nerves work, make muscles squeeze together, help
blood clot, and help the heart to work. Almost all of the calcium in the body
is stored in bone. The rest is found in the blood.
level of calcium in the blood is carefully controlled. When blood calcium
levels get low (hypocalcemia), the bones release calcium to bring it
back to a good blood level. When blood calcium levels get high (hypercalcemia), the extra calcium is stored in the
bones or passed out of the body in urine and stool. The amount of calcium in
the body depends on the amount of:
Vitamin D and these hormones help control the amount of
calcium in the body. They also control the amount of calcium you absorb from
food and the amount passed from the body in urine. The blood levels of
phosphate are closely linked to calcium levels and they work in opposite ways:
As blood calcium levels get high, phosphate levels get low, and the opposite is
It is important to get the right amount of calcium in
your food because the body loses calcium every day. Foods rich in calcium are
dairy products (milk, cheese), eggs, fish, green vegetables, and fruit. Most
people who have low or high levels of calcium do not have any symptoms. Calcium
levels need to be very high or low to cause symptoms.
High calcium levels in the urine can cause kidney
Why It Is Done
A urine calcium test is done to:
- See whether a
kidney stone has developed because of high amounts of
calcium in the urine.
- See how much calcium you are getting in your diet and how well it's being absorbed by your intestines.
- Look for problems that cause your bones to lose calcium.
- See how well your kidneys are working.
- Check for problems with the
A urine calcium test is not as helpful as a blood calcium
test to find certain conditions, such as hyperparathyroidism, bone diseases, or
How To Prepare
You may be asked to follow a special
diet that is either high or low in calcium for several days before the