Calcium Blood Test
Reviewed
Also called: Total Calcium, Ionized Calcium, Ca Blood Test
A calcium blood test measures the amount of calcium in your blood. Calcium is one of the most important minerals in your body.
Specimen: Blood
Why this test may be ordered
- To check your general health as part of a routine checkup
- To help diagnose or monitor conditions that affect your bones, kidneys, digestive system, thyroid, and parathyroid glands
- If you have symptoms of high calcium levels such as constipation, nausea, increased thirst, or fatigue
- If you have symptoms of low calcium levels such as muscle cramps, tingling in lips or fingers, or irregular heartbeat
- If you have a known condition that may affect calcium levels, such as kidney disease, thyroid disease, or certain cancers
Preparation and collection
You usually don't need any special preparations for a calcium blood test or a basic or comprehensive metabolic panel. You may need to stop taking certain medicines or supplements, such as vitamin D, so tell your provider about everything you take. But don't stop taking any medicines unless your provider tells you to.
A health care professional will take a blood sample from a vein in your arm, using a small needle. This usually takes less than five minutes.
There is very little risk to having a blood test. You may have slight pain or bruising at the spot where the needle was put in, but most symptoms go away quickly.
Understanding results
If your results from a total calcium blood test are not in the normal range, it doesn't always mean that you have a medical condition that needs treatment.
What does high calcium (hypercalcemia) mean?
Higher than normal (hypercalcemia): Results from a total calcium test that are higher than normal (hypercalcemia) may be a sign of many types of conditions, such as: overactive parathyroid glands (hyperparathyroidism), a condition in which your parathyroid glands produce too much parathyroid hormone, certain types of cancer, including cancer that spreads to the bone, bone disorders, including Paget's disease of bone, taking too much vitamin D over a long period of time. Limitation: Your diet and certain medicines can affect your calcium levels. Next step: If you have questions about your results, talk with your provider.- Lower than normal (hypocalcemia): Results from a total calcium test that are lower than normal (hypocalcemia) may be a sign of: low blood protein levels, which may be caused by liver disease or malnutrition, underactive parathyroid glands (hypoparathyroidism), a condition in which your parathyroid glands produce too little parathyroid hormone, too little calcium in your diet, too little vitamin D or magnesium, pancreatitis, kidney disease. Limitation: Your diet and certain medicines can affect your calcium levels. Next step: If you have questions about your results, talk with your provider.
- A calcium blood test does not tell you how much calcium is in your bones.
- Results that are not in the normal range do not always mean you have a medical condition that needs treatment; diet and certain medicines can affect calcium levels.
- The test measures total calcium, which includes both bound and free calcium; an ionized calcium test may be needed if total calcium results are not normal.
What to do next
If you have questions about your results, talk with your provider.
- What do my calcium test results mean for my health?
- Do I need any additional tests based on my calcium level?
- Should I change my diet or medications because of my calcium level?
- What symptoms should I watch for that might indicate a problem with my calcium levels?
- How often should I have my calcium levels checked?
Evidence source
Source: U.S. National Library of Medicine (MedlinePlus). Practices and reference ranges may differ in your country.