Health Library Explorer

Calcium (Blood)

Does this test have other names?

Total calcium, ionized calcium

What is this test?

A calcium blood test measures how much calcium is in your blood. Your healthcare provider can use this test to help diagnose and watch many conditions. There are 2 types of calcium blood tests. One is total calcium and the other is ionized calcium. Ionized calcium measures the "free" calcium in your blood. This is the calcium not bound to other parts of the blood. 

Why do I need this test?

You may need this test if your healthcare provider is trying to diagnose a variety of disorders. These include kidney disease, pancreatitis, and disease of the parathyroid gland. Calcium levels may also be abnormal in many types of cancer. Your provider might also order this test as part of a routine health check.



What other tests might I have along with this test?

Calcium can be tested for a number of reasons. Other tests will vary based on what your healthcare provider is looking for. 

Your provider may also order tests to check kidney function, vitamin D, phosphorus levels, and parathyroid hormone. These tests can help figure out what is causing your abnormal calcium levels.

What do my test results mean?


A normal range of total blood calcium in adults is usually between 8.5 and 10.3 milligrams/deciliter (mg/dL). Normal ionized calcium level generally ranges between 4.6 to 5.3 mg/dL. 

How is this test done?


Does this test pose any risks?


What might affect my test results?

A number of things can affect the results of a calcium blood test. This test is typically done at the same time as other blood tests to get a better picture of your overall health. Certain medicines, such as certain types of diuretics, can change blood calcium levels and affect the test results. 

How do I get ready for this test?


Online Medical Reviewer: Chad Haldeman-Englert MD
Online Medical Reviewer: Kenny Turley PA-C
Online Medical Reviewer: Maryann Foley RN BSN
Date Last Reviewed: 9/1/2020
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