Calcium is an important mineral, which your body uses in many ways. It increases the strength of the bones and teeth and also helps the muscles and nerves to function.
There are several different forms of calcium in your blood. These forms include ionized calcium, calcium, bound to other minerals called anions and calcium, bound to proteins such as albumin.
Ionized calcium, also known as free calcium, is the most active form.
A serum calcium test usually checks the total amount of calcium in the blood. This includes ionized calcium and calcium, bound to proteins and anions. The calcium levels in your blood are usually checked, if you have symptoms of kidney disease, certain cancers or parathyroid gland problems.
Ionized calcium levels provide more information on active ionized calcium. If the balance between bound calcium and free calcium is not normal, it is important to understand why.
Free calcium usually makes up half of your body's total calcium. An imbalance can be a sign of a serious health problem.
When to test ionized calcium:
- in case of blood transfusion;
- if you are very ill;
- if you are on intravenous fluids;
- if you have a severe surgery;
- if the blood protein levels are not normal.
In these cases, it is important to know exactly how much free calcium you have available. Low levels of free calcium can slow or speed up the heart rate, cause muscle spasms and even lead to coma.
