Nutrients
Calcium (total)
Ca
Included in Baseline and Complete.
Compare membershipsWhy your body guards its blood calcium so closely.
Calcium is best known for building bones and teeth, and the small amount in your blood is essential for nerves, muscles, heart rhythm, and blood clotting. Your body keeps blood calcium within a narrow range.
Blood calcium says little about your bones.
Nearly all of your body's calcium is stored in your bones. When you take in too little, your body draws on that reserve to keep blood levels steady, so a typical result doesn't show whether your intake or bone density is adequate.
Blood calcium does reflect how well your parathyroid glands, kidneys, and vitamin D are regulating it. Close to half of blood calcium is attached to proteins, mainly albumin, so a low albumin can make total calcium look low.
Your bones lend calcium to your blood whenever it runs short.
Questions
What can cause a high calcium result?
An overactive parathyroid gland is one of the most common causes. Taking too much vitamin D over time, some medicines, and certain bone or other medical conditions can also raise it. A repeat test, sometimes with ionized calcium, often helps clarify the result.
What can cause a low calcium result?
Low albumin is a common reason, since it lowers total calcium without changing the active portion. Low vitamin D or magnesium, kidney disease, and underactive parathyroid glands are other causes. A clinician can decide whether a repeat or ionized calcium test is needed.