Calcium - ionized Ionized calcium is calcium that is freely
flowing in your blood and not attached to proteins. It is also
called free calcium. All cells need calcium in order to work.
Calcium helps build strong bones and teeth. It is important for
heart function, and helps with muscle contraction, nerve
signaling, and blood clotting. This article discusses the test
used to measure the amount of ionized calcium in blood. See
also: Serum calcium Free calcium; Ionized calcium How the test
is performed Usually the blood is drawn from the wrist. However,
it may also be drawn from the inside of the elbow, groin, or
other artery. A heartbeat (pulse) is felt by pressing on the
area above an artery. The doctor will usually check to make sure
blood is flowing into the hand from the main arteries in the
forearm (radial and ulnar arteries). The area is cleaned with
antiseptic and a needle is inserted. A small amount of
anesthetic may be injected or applied before the needle is
inserted. The blood will easily flow into t