What is the calcium test?

This test measures the amount of calcium in your blood. Your nerves and muscles, including your heart, need calcium in order to work well. Calcium is also important for healthy bones and teeth.

You get calcium when you eat or drink dairy products and eat some vegetables (such as broccoli) and calcium-fortified food.

Most of the calcium in your body is in your bones. The blood calcium test measures only the small amount of calcium in your blood. This test does not measure the amount of calcium in your bones.

Why is this test done?

This test may help diagnose and treat a medical problem you are having. It does not diagnose a specific problem but it can help your healthcare provider know what other tests you might need. It’s also a way to see how well treatment for a disease is working.

This test may be done to look for or check certain medical conditions, such as:

• Bone disorders
• Gland (hormone) problems
• Blood-clotting problems
• Kidney disease
• Irregular heartbeat

The test may be done because you have symptoms of low calcium (hypocalcemia), such as muscle spasm, cramping, and twitching.

How do I prepare for this test?

• You may need to avoid taking certain medicines before the test because they might affect the test result. Make sure your healthcare provider knows about any medicines, herbs, or supplements that you are taking. Ask your provider before stopping any of your regular medicines.
• Talk to your healthcare provider if you have any questions about the test.

How is the test done?

Having this test will take just a few minutes. A small amount of blood is taken from a vein in your arm with a needle. The blood is collected in tubes and sent to a lab.

Ask your healthcare provider when and how you will get the result of your test.

What does the test result mean?

Some of the reasons your calcium level may be higher than normal are:

• You have taken a lot of vitamins A and D. (Your body uses vitamin D to absorb calcium from the food you eat.)
• You take certain medicines, such as some diuretics, also called “water pills,” used to treat high blood pressure.
• You have been on bed rest for a long time.
• You have a hormone problem.
• You have cancer.

Many other medical conditions can cause a high level of calcium.

Some of the reasons your calcium level may be lower than normal are:

• Your body needs more vitamin D or the mineral magnesium.
• You don’t get enough calcium from your diet.
• Your intestines are not absorbing calcium.
• You take certain medicines, such as cimetidine, a drug that causes your stomach to make less acid.
• You have a hormone problem.
• You have been drinking too much alcohol.
• You have kidney, pancreas, or liver disease.

Your body will take calcium from your bones if the calcium level in your blood is low. So even if you have severe osteoporosis (bone-thinning), your blood level of calcium may be normal.

What if my test result is not normal?

Test results are only one part of a larger picture that takes into account your medical history, physical exam, and current health. Sometimes a test needs to be repeated to check the first result. Talk to your healthcare provider about your result and ask questions, such as:

• If you need more tests
• What kind of treatment you might need
• What lifestyle, diet, or other changes you might need to make