This test measures the amount of calcium in the blood or serum. Calcium is one of the important electrolytes or minerals that is found in the body. Ninety-nine percent of all of the calcium that is found in the body is in the bone. The remaining 1% of the calcium helps the body work. It is needed for the proper functioning of the nerve, heart, and skeletal muscle cells. The right amount of calcium is also vital for the control of hormones. Plus, it helps chemicals called neurotransmitters to send nerve impulses through the body.

Who is a candidate for the test?

This test is ordered to help in the diagnosis of a number of different conditions directly linked with calcium imbalances. One example is diseases of the parathyroid glands. Calcium is also checked when certain other conditions have been diagnosed that may indirectly affect the level of calcium in the body. These may include kidney disease, cancer, or sarcoidosis.

How is the test performed?

A sample of blood is taken from a vein on the forearm or hand. First, the skin over the vein is cleaned with an antiseptic such as alcohol. Next, a rubber tube called a tourniquet is tied around the upper arm. This restricts blood flow in the lower arm veins and causes them to enlarge. And that makes them easier to see and insert a needle into. A fine needle is inserted into the vein, and the tourniquet is then untied. Blood flows from the vein through the needle into a vial. After the needle is withdrawn from the vein, the puncture site is covered with a bandage.