February 5, 2016
Calcium - Ionized
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.
This article discusses the test used to measure the amount of ionized calcium in blood.
Back to TopAlternative Names
Free calcium; Ionized calcium
Back to TopHow to Prepare for the Test
You should not eat or drink for at least 6 hours before the test.
Many medicines can interfere with blood test results.
- Your health care provider will tell you if you need to stop taking any medicines before you have this test.
- Do not stop or change your medications without talking to your doctor first.
Back to TopWhy the Test Is Performed
Your doctor may order this test if you have signs of kidney or parathyroid disease. The test may also be done to monitor 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.
Back to TopNormal Results
- Children: 4.4 - 6.0 milligrams per deciliter (mg/dL)
- Adults: 4.4 - 5.3 mg/dL
Normal value ranges may vary slightly among different laboratories. Talk to your doctor 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.
Back to TopWhat 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
- Milk-alkali syndrome
- Multiple myeloma
- Paget's disease
- Thiazide diuretics
- Thrombocytosis (high platelet count)
- Vitamin A excess
- Vitamin D excess
Lower-than-normal levels may be due to:
Back to TopReferences
Wysolmerski JJ, Insogna KL. The parathyroid glands, hypercalcemia, and hypocalcemia. In: Goldman L, Schafer AI, eds. Cecil Medicine . 24th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 253.
MOST POPULAR - HEALTH
- Well: A Diet and Exercise Plan to Lose Weight and Gain Muscle
- Well: Ask Well: Floaters in the Eye
- Unicef Report Finds Female Genital Cutting to Be Common in Indonesia
- A New Vision for Dreams of the Dying
- Well: Finding a Drug for Healthy Aging
- Well: Sleep Problems Tied to Type 2 Diabetes
- Global Health: Growing Support Among Experts for Zika Advice to Delay Pregnancy
- The New Old Age: Study Finds Growing Reason to Be Wary of Some Reflux Drugs
- Well: The Health Benefits of Knitting
- Well: Think Like a Doctor: Drowning on Dry Land Solved