Calcium Most Popular

The Calcium test contains 1 test with 1 biomarker.

Description: A Calcium test is a blood test that is used to screen for, diagnose, and monitor a wide range of medical conditions.

Also Known As: Ca Test, Serum Calcium Test, Calcium Blood Test

Collection Method: Blood Draw

Specimen Type: Serum

Test Preparation: No preparation required

Average Processing Time: 1 to 2 days

When is a Calcium test ordered?

A blood calcium test is frequently requested during a general medical evaluation. It's usually part of the comprehensive metabolic panel or the basic metabolic panel, two sets of tests that can be done during an initial evaluation or as part of a routine medical checks.

Many people do not experience symptoms of high or low calcium until their levels are dangerously high or low.

When a person has certain types of cancer, kidney illness, or has had a kidney transplant, calcium monitoring may be required. When someone is being treated for abnormal calcium levels, monitoring may be required to determine the effectiveness of medications such as calcium or vitamin D supplements.

What does a Calcium blood test check for?

Calcium is one of the most plentiful and vital minerals in the human body. It is required for cell signaling as well as the proper operation of muscles, nerves, and the heart. Calcium is essential for blood clotting as well as bone growth, density, and maintenance. This test determines how much calcium is present in the blood.

Calcium is found complexed in the bones for 99 percent of the time, while the remaining 1% circulates in the blood. Calcium levels are closely monitored; if too little is absorbed or consumed, or if too much is lost through the kidney or stomach, calcium is removed from bone to keep blood concentrations stable. Approximately half of the calcium in the blood is metabolically active and "free." The other half is "bound" to albumin, with a minor proportion complexed to anions like phosphate, and both of these forms are metabolically inactive.

Blood calcium can be measured using two different tests. The free and bound forms of calcium are measured in the total calcium test. Only the free, physiologically active form of calcium is measured in the ionized calcium test.

Lab tests often ordered with a Calcium test:

  • Phosphorus
  • Vitamin D
  • Magnesium
  • PTH
  • Albumin
  • Basic Metabolic Panel (BMP)
  • Comprehensive Metabolic Panel (CMP)

Conditions where a Calcium test is recommended:

  • Kidney Disease
  • Thyroid Disease
  • Alcoholism
  • Malnutrition
  • Parathyroid Diseases
  • Breast Cancer
  • Multiple Myeloma

How does my health care provider use a Calcium test?

A blood calcium test is used to screen for, diagnose, and monitor a variety of bone, heart, nerve, kidney, and tooth disorders. If a person has signs of a parathyroid disease, malabsorption, or an overactive thyroid, the test may be ordered.

A total calcium level is frequently checked as part of a standard health check. It's part of the comprehensive metabolic panel and the basic metabolic panel, which are both collections of tests used to diagnose or monitor a range of ailments.

When a total calcium result is abnormal, it is interpreted as a sign of an underlying disease. Additional tests to assess ionized calcium, urine calcium, phosphorus, magnesium, vitamin D, parathyroid hormone, and PTH-related peptide are frequently performed to assist determine the underlying problem. PTH and vitamin D are in charge of keeping calcium levels in the blood within a narrow range of values.

Measuring calcium and PTH combined can assist identify whether the parathyroid glands are functioning normally if the calcium is abnormal. Testing for vitamin D, phosphorus, and/or magnesium can assist evaluate whether the kidneys are excreting the right amount of calcium, and measuring urine calcium can help detect whether additional deficits or excesses exist. The balance of these many compounds is frequently just as critical as their concentrations.

The total calcium test is the most common test used to determine calcium status. Because the balance between free and bound calcium is usually constant and predictable, it is a reliable reflection of the quantity of free calcium present in the blood in most cases. However, the balance between bound and free calcium is altered in some persons, and total calcium is not a good indicator of calcium status. Ionized calcium measurement may be required in certain cases. Critically sick patients, those receiving blood transfusions or intravenous fluids, patients undergoing major surgery, and persons with blood protein disorders such low albumin are all candidates for ionized calcium testing.

What do my Calcium test results mean?

The amount of calcium circulating in the blood is not the same as the amount of calcium in the bones.

A feedback loop including PTH and vitamin D regulates and stabilizes calcium uptake, utilization, and excretion. Conditions and disorders that disturb calcium control can induce abnormal acute or chronic calcium elevations or declines, resulting in hypercalcemia or hypocalcemia symptoms.

Total calcium is usually tested instead of ionized calcium since it is easier to do and requires no additional treatment of the blood sample. Because the free and bound forms of calcium make up about half of the total, total calcium is usually a decent depiction of free calcium. Because nearly half of the calcium in blood is bonded to protein, high or low protein levels might alter total calcium test findings. In these circumstances, an ionized calcium test is more appropriate for measuring free calcium.

A normal total or ionized calcium test, when combined with other normal laboratory findings, indicates that a person's calcium metabolism is normal and blood levels are properly managed.

We advise having your results reviewed by a licensed medical healthcare professional for proper interpretation of your results.

The following is a list of what is included in the item above. Click the test(s) below to view what biomarkers are measured along with an explanation of what the biomarker is measuring.


You have more calcium in your body than any other mineral. Calcium has many important jobs. The body stores more than 99 percent of its calcium in the bones and teeth to help make and keep them strong. The rest is throughout the body in blood, muscle and the fluid between cells. Your body needs calcium to help muscles and blood vessels contract and expand, to secrete hormones and enzymes and to send messages through the nervous system.
*Process times are an estimate and are not guaranteed. The lab may need additional time due to weather, holidays, confirmation/repeat testing, or equipment maintenance.

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