OVERVIEW
Ionized calcium is calcium in your blood that is 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. It also helps with muscle contraction, nerve signaling, and blood clotting.
INTERPRETATIONS
Normal Results
Results generally fall in these ranges:
Children: 4.8 to 5.3 milligrams per deciliter (mg/dL) or 1.20 to 1.32 millimoles per liter (millimol/L)
Adults: 4.8 to 5.6 mg/dL or 1.20 to 1.40 millimol/L
Normal value ranges may vary slightly among different laboratories. Talk to your provider about the meaning of your specific test results.
The examples above show the common measurements for results for these tests. Some laboratories use different measurements or may test different specimens.
What Abnormal Results Mean
Higher-than-normal levels of ionized calcium may be due to:
- Decreased levels of calcium in the urine from an unknown cause
- Hyperparathyroidism
- Hyperthyroidism
- Milk-alkali syndrome
- Multiple myeloma
- Paget disease
- Sarcoidosis
- Thiazide diuretics
- Thrombocytosis (high platelet count)
- Tumors
- Vitamin A excess
- Vitamin D excess
Lower-than-normal levels may be due to:
- Hypoparathyroidism
- Malabsorption
- Osteomalacia
- Pancreatitis
- Renal failure
- Rickets
- Vitamin D deficiency
WHY GET TESTED?
Your provider may order this test if you have signs of kidney or parathyroid disease. The test may also be done to monitor the progress and treatment of these diseases.
Most of the time, blood tests measure your total calcium level. This looks at both ionized calcium and calcium attached to proteins. You may need to have a separate ionized calcium test if you have factors that increase or decrease total calcium levels. These may include abnormal blood levels of albumin or immunoglobulins.