Calcium Blood Test: Uses, Preparation and Results
The quantity of calcium in your blood is measured by a calcium blood test. Too high or too low calcium in the blood can indicate a variety of medical issues, including bone disease, thyroid illness, parathyroid abnormalities, kidney disease, and others.
One of the most vital elements in your body is calcium. Your blood contains around 1% of the calcium in your body. The rest is held in your bones and teeth. The appropriate quantity of calcium in your blood is required for your neurons, muscles, and heart to function properly. It also aids blood vessels' movement throughout the body and releases hormones that impact various bodily processes.
Other names: total calcium, ionized calcium
What is Calcium Blood Test used for?
A blood calcium test is used for general health. It's also used to diagnose or monitor many types of medical conditions, including conditions that affect your bones, kidneys, digestive system, thyroid, and parathyroid glands.
There are two types of calcium blood tests that measure different forms of blood calcium:
- Total calcium test: It measures all the calcium in the blood. There are two types of blood calcium that are normally present in about equal amounts:
- "Bound calcium" is attached to proteins in the blood.
- "Free calcium" is not attached to proteins. It's also called ionized calcium. This form of blood calcium is active in many body functions.
Because your body normally regulates the balance of bound and ionized calcium, a total calcium test provides an accurate indication of how much ionized calcium you have.
The most frequent blood calcium test is a total calcium test. It is frequently included in a basic metabolic panel (BMP) or a comprehensive metabolic panel (CMP), both of which are common screening procedures.
- An ionized calcium test:It only detects "free calcium" in the blood which is not bound to proteins. Because an ionized calcium test is more difficult to perform, it is only requested when the findings of a total calcium test are abnormal. One may also be subjected to this test if they have a disease that impairs the body's capacity to balance the levels of ionized and bound calcium in their blood, are critically unwell or are undergoing surgery.
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Why do I need a Calcium Blood Test?
As part of your routine examination, your doctor may have prescribed a basic or complete metabolic panel, which includes a calcium blood test.
This test may also be used to detect or monitor disorders that impact your blood calcium levels, or if you have symptoms of abnormal calcium levels.
High calcium levels might cause the following symptoms:
Symptoms of low calcium levels include:
Many people who have raised or low calcium levels are asymptomatic. If you have a known ailment such as mentioned below that may alter your calcium levels, your physician may request a calcium test.
- Kidney disease
- Thyroid or parathyroid disease
- Malnutrition
- Problems absorbing calcium
- Certain types of cancer
What happens during a calcium blood test?
During a calcium blood test a small needle will be used by a healthcare expert to draw blood from a vein. After the insertion of the needle, a little quantity of blood will be collected as a sample in a test tube or vial. You may feel a slight sting or discomfort when the needle goes in or out. This normally takes five minutes.
How to prepare for the test?
A calcium blood test, as well as a simple or complete metabolic panel, normally does not require any particular preparation. To ensure that your test results are correct, your physician may advise you to discontinue taking certain medications or supplements, such as vitamin D.
If your provider has requested further tests on your blood sample, you may be required to fast (not eat or drink anything) for several hours prior to the test. If there are any particular instructions to follow, your doctor will notify you.
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Is there any risk in the test?
Having a blood test poses relatively no risk or danger. The risks of a calcium blood test are minimal; you may experience slight discomfort or bruising where the needle was inserted, but this typically fades quickly.
What do the results of the calcium blood test mean?
A total calcium test result that is greater than normal (high calcium blood level) may indicate various issues, including:
- Hyperparathyroidism (excess hormone from parathyroid glands)
- Certain cancers, especially those that spread to bones
- Bone disorders, such as Paget’s disease
- Excessive, long-term vitamin D intake
- Conditions like lung or kidney disease, or hyperthyroidism
- Certain medications that increase calcium
A lower-than-normal (low calcium blood level) result may indicate:
- Low protein levels in the blood (linked to liver disease or malnutrition)
- Hypoparathyroidism (underactive parathyroid glands)
- Insufficient calcium intake, vitamin D, or magnesium levels
- Conditions like kidney disease or pancreatitis
Normal adult blood calcium levels are generally 8.5 to 10.2 mg/dL (2.15 to 2.55 mmol/L), but ranges can vary by lab. Low or high levels don’t always signal a health issue, as diet and medications may affect calcium levels. Consult your doctor if you have questions about your results.
Important Information on Calcium Blood Test
A calcium blood test does not reveal the amount of calcium in your bones. A bone density scan, known as a DEXA scan, may be used to assess bone health. A DEXA scan evaluates the mineral composition of your bones, including calcium, as well as other factors.
