Calcium blood test

To measure the total amount of calcium in the blood. About half of the calcium in the blood is bound to proteins, mainly albumin. For this reason, the blood calcium test can be misleading, and tests are sometimes needed to confirm the result. A separate test measures calcium that is not bound to proteins in the blood. This calcium is called ionized or free calcium. Calcium can also be measured in urine.


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  • 1 How the test is performed
  • 2 How the test will feel
  • 3 Your doctor may order this test if you have signs or symptoms of
  • 4 Normal values
  • 5 Common causes include:
  • 6 Levels below normal may be due to
  • 7 Risks
  • 8 Other risks associated with having blood drawn are slight, but can be:
  • 9 Sources

How the test is performed

A blood sample is needed. Preparation for the exam

Your doctor may ask you to temporarily stop taking certain medications that may affect the test. These medications include:

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

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

How the test will feel

When the needle is inserted to draw blood, some people feel moderate pain; others just feel a prick or stinging sensation. Afterward, there may be some throbbing or a slight bruise, which soon disappears. Reasons the test is done

All cells need calcium to work. Calcium helps build strong bones and teeth. It is important for heart function and helps with muscle contraction, nerve signals, 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 or breast, lung, neck, and kidney cancer
  • Chronic kidney disease
  • Chronic liver disease
  • Parathyroid gland disorders
  • Disorders that affect the way the intestines absorb nutrients
  • Overactive thyroid or taking too much thyroid hormone medicine

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

Normal values

Normal values ​​range from 8.5 to 10.2 mg / dL.

The ranges of normal values ​​may vary slightly between different laboratories . Some labs use different measurements or may test different samples. Talk to your doctor about the meaning of your specific test results. Meaning of abnormal results

Levels above normal can be due to many health problems.

Common causes include:

  • Being on bed rest for a long time
  • Taking too much calcium or vitamin D
  • Hyperparathyroidism
  • Infections that cause granulomas, such as tuberculosis and certain mycobacterial and fungal infections
  • Metastatic bone tumor
  • Multiple myeloma
  • Osteomalacia
  • An overactive thyroid gland (hyperthyroidism) or too much thyroid hormone replacement medicine
  • Paget’s disease
  • Sarcoidosis
  • Tumors that produce a substance similar to parathyroid hormone
  • Use of certain medications, such as lithium, tamoxifen, and thiazides

Levels below normal may be due to

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


There is very little risk in taking a blood sample. The size of veins and arteries varies from person to person and from one side of the body to the other. Drawing blood from some people can be more difficult than from others.

Other risks associated with having blood drawn are slight, but can be:

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


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