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. 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.
Normally the 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 also true.
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 stones.
Why It Is Done
A urine calcium test is done to:
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 test.
How It Is Done
Urine calcium is measured in a sample taken from all the urine made in a 24-hour period.
How It Feels
There is no pain while collecting a 24-hour urine sample.
There is no chance for problems while collecting a 24-hour urine sample.
A test for calcium in urine is a 24-hour test that checks the amount of calcium that is passed from the body.
The normal values listed here—called a reference range—are just a guide. These ranges vary from lab to lab, and your lab may have a different range for what's normal. Your lab report should contain the range your lab uses. Also, your doctor will evaluate your results based on your health and other factors. This means that a value that falls outside the normal values listed here may still be normal for you or your lab.
Test results may be affected by the amount of calcium in the diet.
High values of calcium in the urine may be caused by:
In some cases, calcium in the urine may be high for other reasons. One example of this is idiopathic familial hypocalciuric hypercalcemia.
Low values of calcium in the urine may be caused by:
What Affects the Test
Reasons you may not be able to have the test or why the results may not be helpful include:
What To Think About
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