Lab Tests

What do the results of a serum calcium test mean?

A Answers (1)

  • AHealthwise answered

    A test for calcium in the blood checks the calcium level in the body that is not stored in the bones.


    The normal values listed here—called a reference range—are just a guide. These ranges vary from lab to lab, and your lab may have a different range for what’s normal. Your lab report should contain the range your lab uses. Also, your doctor will evaluate your results based on your health and other factors. This means that a value that falls outside the normal values listed here may still be normal for you or your lab.

    Total calcium 
    • Adults: 8.8–10.4 milligrams per deciliter (mg/dL) or 2.2–2.6 millimoles per liter (mmol/L)
      Normal blood calcium values are lower in older people. Normal blood calcium are higher in children because their bones are growing quickly.
      • Children: 6.7–10.7 milligrams per deciliter (mg/dL) or 1.90–2.75 millimoles per liter (mmol/L)

      6.7%u201310.7 milligrams per deciliter (mg/dL) or 1.90%u20132.75 millimoles per liter (mmol/L)

      An ionized calcium test checks the amount of calcium that is not attached to protein in the blood. The level of ionized calcium in the blood is not affected by the amount of protein in the blood.

      Ionized calcium
      Adults: 4.65–5.28 mg/dL or 1.16–1.32 mmol/L Children:   4.80–5.52 mg/dL or 1.20–1.38 mmol/L

      High values

      High values of calcium may be caused by:

      • Hyperparathyroidism.
      • Cancer, including cancer that has spread to the bones.
      • Tuberculosis.
      • Being on bed rest for a long time after a broken bone.
      • Paget's disease.

      Low values

      Low values of calcium may be caused by:

      • A low level of the blood protein albumin (hypoalbuminemia).
      • Hypoparathyroidism.
      • High levels of phosphate in the blood, which can be caused by kidney failure, laxative use and other things.
      • Malnutrition caused by diseases such as celiac disease, pancreatitis, and alcoholism.
      • Osteomalacia.
      • Rickets.

      This information does not replace the advice of a doctor. Healthwise disclaims any warranty or liability for your use of this information. To learn more visit

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