What is serum calcium?

The term serum calcium indicates the levels of calcium found in the blood of a person. Calcium is the most abundant mineral element in the human body. Approximately 98% of the 1200 g of calcium in adults is in the form of hydroxyapatite in the skeleton. Serum calcium indicates whether we are calcium deficient or have abnormally high levels of calcium in our blood stream, these conditions are known as hypocalcaemia and hypercalcaemia. Circulating calcium is largely linked to plasma proteins and only a small amount is present in the free form.

Extremely low levels of calcium in the blood can lead to fatigue, muscle cramps, indigestion, osteoporosis and other health problems. Hence the fact that calcium deficiency may indicate that the parathyroid glands are not working properly and that a very small amount of parathyroid hormone is being produced by them. Hypocalcaemia also indicates that we are not consuming enough calcium from our daily diet. However it may be that large amounts of calcium is lost from our body though urine because of a high protein diet, or due to consuming large amounts of sugar or too much phosphoric acid in our daily diet. Abnormally high levels of calcium in the blood are sometimes caused due to hyperactivity of the parathyroid glands.

There are other conditions, such as that of high blood pressure, hypercalcaemia and the complications associated with this condition are the outcomes of abnormally high serum calcium in the blood stream.


Why measure the level of serum calcium?

Generally we need about 1000mg of calcium on a daily basis, because if this requirement is not meet the blood is unable to receive calcium from food, and starts acquiring it from the bones to carry out various activities, such as those of proper circulation, absorption of other minerals, proper digestions, blood clotting, and other important functions necessary for daily life.

The test will measure the levels of serum calcium present in the circulation of the body, as cells need calcium in order to function. Calcium helps build strong bones and teeth, it is important to heart function, and helps with muscle contractions, nerve signaling and blood clotting. The test is routine, but it can also be prescribed in the monitoring of certain diseases such as kidney disease, parathyroid disease or any symptoms that signal an abnormal calcium metabolism.

Normal test values range from 8.5 to 10.2 mg/dL.


Standard of preparation

Sampling is usually done in the morning in the hospital. There are no special preparations needed for this test. The doctor will advise and recommend if you need to be fasting prior to the blood examination. You should inform your doctor of any medication you are taking prior to the exam, as some medical treatments may interfere with the blood results.


Is the examination painful or dangerous?

The examination is neither painful nor dangerous. The patient may feel a tingling sensation with the entrance of the needle in the arm when blood is being extracted for examination.


How is the exam performed?

The exam consists of a simple blood sample test.