Navigate Up

Orthopaedics Center - A-Z Index

#
I
Q
Y
Z

Print This Page

Calcium blood test

The calcium blood test measures the level of calcium in the blood.

This article discusses the test to measure the total amount of calcium in your blood. About half of the calcium in the blood is attached to proteins, mainly albumin. For this reason, the calcium blood test can be misleading, and sometimes needs tests to confirm the result.

A separate test measures calcium that is not attached to proteins in your blood. Such calcium is called free or ionized calcium .

Calcium can also be measured in the urine .

Alternative Names

Ca+2; Serum calcium; Ca++

How the Test is Performed

A blood sample is needed.

How to Prepare for the Test

The health care provider may tell you to temporarily stop taking certain medicines that can affect the test. Medicines include:

  • Calcium salts (may be found in nutritional supplements or antacids)
  • Lithium
  • Thiazide diuretics
  • Thyroxine
  • Vitamin D

Drinking too much milk (two or more quarts a day or having an equivalent amount of other dairy products ) or taking too much vitamin D as a dietary supplement can also increase blood calcium levels.

How the Test will Feel

When the needle is inserted to draw blood, some people feel moderate pain. Others feel only a prick or stinging sensation. Afterward, there may be some throbbing or slight bruising. These soon go away.

Why the Test is Performed

All cells need calcium in order to work. Calcium helps build strong bones and teeth. It is important for heart function, and helps with muscle contraction, nerve signaling, and blood clotting.

Your doctor may order this test if you have signs or symptoms of:

  • Certain bone diseases
  • Certain cancers, such as multiple myeloma, a cancer of the breast, lung, neck, and kidney
  • Chronic kidney disease
  • Chronic liver disease  
  • Disorders of the parathyroid gland
  • Disorders that affect how your intestines absorb nutrients
  • Overactive thyroid gland or taking too much thyroid hormone medication

Your doctor may also order this test if you have been on bed rest for a long time.

Normal Risks

Normal values range from 8.5 to 10.2 mg/dL.

Normal value ranges may vary slightly among different laboratories. Some laboratories use different measurements or may test different specimens. Talk to your doctor about the meaning of your specific test results.

What Abnormal Results Mean

Higher than normal levels may be due to a number of health conditions. Common causes include:

  • Being on bed rest for a long time
  • Consuming too much calcium or vitamin D
  • HIV/AIDS
  • Hyperparathyroidism
  • Infections that cause granulomas such as tuberculosis and certain fungal and mycobacterial infections
  • Metastatic bone tumor
  • Multiple myeloma
  • Osteomalacia
  • Overactive thyroid gland (hyperthyroidism) or too much thyroid hormone replacement medication
  • Paget's disease
  • Sarcoidosis
  • Tumors producing a parathyroid hormone-like substance
  • Use of certain medications such as lithium, tamoxifen, and thiazides

Lower than normal levels may be due to:

  • Disorders that affect absorption of nutrients from the intestines
  • Hypoparathyroidism
  • Kidney failure
  • Low blood level of albumin
  • Liver disease
  • Magnesium deficiency
  • Osteomalacia
  • Pancreatitis
  • Vitamin D deficiency

Risks

There is very little risk involved with having your blood taken. Veins and arteries vary in size from one patient to another and from one side of the body to the other. Taking blood from some people may be more difficult than from others.

Other risks associated with having blood drawn are slight but may include:

  • Excessive bleeding
  • Fainting or feeling lightheaded
  • Hematoma (blood accumulating under the skin)
  • Infection (a slight risk any time the skin is broken)
  • Multiple punctures to locate veins

References

Pincus MR, Abraham NZ Jr. Interpreting laboratory results. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 22nd ed. Philadelphia, Pa: Elsevier Saunders; 2011:chap 8.

Wysolmerski JJ, Insogna KL. The parathyroid glands, hypercalcemia, and hypocalcemia. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine. 24th ed. Philadelphia, Pa: Elsevier Saunders; 2011:chap 253.

Updated: 10/29/2013

David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Bethanne Black, and the A.D.A.M. Editorial team.


©  UPMC | Affiliated with the University of Pittsburgh Schools of the Health Sciences
Supplemental content provided by A.D.A.M. Health Solutions. All rights reserved.

For help in finding a doctor or health service that suits your needs, call the UPMC Referral Service at 412-647-UPMC (8762) or 1-800-533-UPMC (8762). Select option 1.

UPMC is an equal opportunity employer. UPMC policy prohibits discrimination or harassment on the basis of race, color, religion, ancestry, national origin, age, sex, genetics, sexual orientation, marital status, familial status, disability, veteran status, or any other legally protected group status. Further, UPMC will continue to support and promote equal employment opportunity, human dignity, and racial, ethnic, and cultural diversity. This policy applies to admissions, employment, and access to and treatment in UPMC programs and activities. This commitment is made by UPMC in accordance with federal, state, and/or local laws and regulations.

Medical information made available on UPMC.com is not intended to be used as a substitute for professional medical advice, diagnosis, or treatment. You should not rely entirely on this information for your health care needs. Ask your own doctor or health care provider any specific medical questions that you have. Further, UPMC.com is not a tool to be used in the case of an emergency. If an emergency arises, you should seek appropriate emergency medical services.

For UPMC Mercy Patients: As a Catholic hospital, UPMC Mercy abides by the Ethical and Religious Directives for Catholic Health Care Services, as determined by the United States Conference of Catholic Bishops. As such, UPMC Mercy neither endorses nor provides medical practices and/or procedures that contradict the moral teachings of the Roman Catholic Church.

© UPMC
Pittsburgh, PA, USA UPMC.com