Calcium Blood Test Test
A calcium blood test measures the amount of calcium in your blood. Too much or too little calcium may be a sign of various medical conditions, such as bone disease, thyroid disease, or kidney disease.
What this test measures
This test measures the amount of calcium in your blood. There are two types: total calcium (measures all calcium) and ionized calcium (measures only free calcium).
What your results mean
Reference ranges vary by laboratory and by your age and sex. MedlinePlus does not publish a single normal range for this test — always read your result against the range printed on your own lab report and discuss it with your provider.
Higher-than-normal results
Results higher than normal (hypercalcemia) may be a sign of overactive parathyroid glands, certain types of cancer, bone disorders like Paget's disease, or taking too much vitamin D over a long period.
Lower-than-normal results
Results lower than normal (hypocalcemia) may be a sign of low blood protein levels, underactive parathyroid glands, too little calcium in diet, too little vitamin D or magnesium, pancreatitis, or kidney disease.
Frequently asked questions
What does a calcium blood test measure?
It measures the amount of calcium in your blood. There are two types: total calcium (all calcium) and ionized calcium (free calcium).
Why is calcium important?
Calcium is necessary for your nerves, muscles, and heart to work properly. It also helps blood vessels move blood and helps release hormones.
What can cause high calcium levels?
High calcium may be caused by overactive parathyroid glands, certain cancers, bone disorders, or taking too much vitamin D over a long period.
What can cause low calcium levels?
Low calcium may be caused by low blood protein levels, underactive parathyroid glands, too little calcium in diet, too little vitamin D or magnesium, pancreatitis, or kidney disease.
Do abnormal results always mean a medical condition?
No. Your diet and certain medicines can affect calcium levels. Talk with your provider if you have questions about your results.
Related lab tests
Sources
- MedlinePlus: Calcium Blood Test — NIH MedlinePlus
Last updated . Information is aggregated from official public sources and is not a substitute for professional medical care.