Ionized calcium (ICa)
Why this test?
The indicator of total blood calcium is often enough for a preliminary assessment of calcium metabolism. It usually reflects the amount of free calcium in the blood, since the balance between bound and free calcium is often stable and quite predictable.
However, in some people, this ratio is disturbed, so that the level of total calcium is not a criterion for evaluating the entire calcium metabolism.
In such cases, ionized calcium testing becomes necessary.
Large fluctuations in the concentration of ionized calcium can cause slowing (bradycardia) and acceleration (tachycardia) of the heart rhythm, muscle spasm, confusion or even coma.
In more severe cases, periodic determination of the content of ionized calcium is especially important for prescribing further treatment and prevention of more serious complications.
In what cases is it prescribed?
In complex with a parathyroid hormone test - their concentrations are checked in people with chronic renal failure to diagnose hyperthyroidism caused by the retention of phosphates in the body, as well as to monitor the results of treatment.
If an increase in the level of ionized calcium is suspected: weakness, rapid fatigue, loss of appetite, constipation, frequent urination, vomiting, thirst. If a decrease in the level of ionized calcium is suspected: spastic pains in the abdomen, fingers trembling, muscle twitching, numbness of the hands and the skin around the mouth, as well as muscle spasms in the same areas.
When the patient is in a critical condition and receives intravenous solutions and blood substitute fluids. In the preoperative period.
In case of albumin disorders.
Test information
Calcium is a vital mineral that enters the body with food.
Functions of calcium: formation of the bone frame, participation in the conduction of neuromuscular impulses, in the contraction of cardiac and skeletal muscles, in blood clotting (transformation of prothrombin into thrombin). It is contained in teeth and bones, its "plasma" part is filtered by the kidneys and is mainly reabsorbed in the absence of disturbances in calcium metabolism. Ionized calcium is a cation that circulates freely in the blood and makes up 46-50% of all blood calcium. Its level increases with a decrease in blood pH and decreases with alkalinization. For every 0.1 unit decrease in pH, ionized calcium corresponds to an increase of 1.5-2.5%. Because the level of ionized calcium is independent of the amount of protein in the blood, it is sometimes a more reliable indicator of primary hyperparathyroidism in people with low albumin levels than the level of total blood calcium.
