Calcium test – Why am I having this test?
Calcium test is used to evaluate parathyroid function and calcium metabolism by measuring the amount of calcium in the blood.
This test can help monitor people with overactive parathyroid gland (hyperparathyroidism), kidney failure, kidney transplantation, and various types of cancerous tumors (malignancies). It is also used to monitor calcium levels after large blood transfusions.
What is being tested?
About one half of the total calcium in the blood is bound to proteins (mostly a protein called albumin), and the other half is in its free (ionized) form. This test measures the amount of total calcium in your blood. The ionized calcium level may also be measured.
What kind of sample is taken?
A blood sample is required for this test. It is usually collected by inserting a needle into a blood vessel.
How are the results reported?
Your test results will be reported as values for total calcium or ionized calcium. Your health care provider will compare your results to normal ranges that were established after testing a large group of people (reference ranges). Reference ranges may vary among labs and hospitals. For this test, common reference ranges for the two types of calcium are:
- Total
calcium
- Less than 10 days old: 7.6–10.4 mg/dL or 1.9–2.6 mmol/L.
- Umbilical: 9–11.5 mg/dL or 2.25–2.88 mmol/L.
- 10 days to 2 years old: 9–10.6 mg/dL or 2.3–2.65 mmol/L.
- Child: 8.8–10.8 mg/dL or 2.2–2.7 mmol/L.
- Adult: 9–10.5 mg/dL or 2.25–2.62 mmol/L.
- Ionized
calcium
- Newborn: 4.2–5.58 mg/dL or 1.05–1.37 mmol/L.
- 2 months to 18 years old: 4.8–5.52 mg/dL or 1.2–1.38 mmol/L.
- Adult: 4.5–5.6 mg/dL or 1.05–1.3 mmol/L.
What do the results mean?
Values above the reference ranges could indicate:
- Hyperparathyroidism.
- Lung, breast, or kidney cancer, or metastatic cancer in the bones.
- Infections or conditions that cause increased vitamin D levels.
- Conditions that cause bone destruction.
- Overactive thyroid gland (hyperthyroidism).
- Consumption of too many milk products.
- Side effects from certain medicines.
- Other hormone disorders.
Values below the reference ranges could indicate:
- Underactive parathyroid gland (hypoparathyroidism).
- Kidney failure.
- Vitamin D deficiency or rickets.
- Softening of the bones.
- Poor absorption of calcium.
- Pancreatitis.
- High blood pH (alkalosis).
- Low blood levels of albumin.
Talk with your health care provider about what your results mean.
Questions to ask your health care provider
Ask your health care provider, or the department that is doing the test:
- When will my results be ready?
- How will I get my results?
- What are my treatment options?
- What other tests do I need?
- What are my next steps?
Summary
- The calcium test is used to evaluate parathyroid function and calcium metabolism by measuring the amount of calcium in the blood.
- The calcium test measures the total calcium and can also measure the ionized calcium in your blood.
- Calcium levels above the reference range can be seen in hyperparathyroidism, various cancers, hyperthyroidism, and several other conditions.
- Calcium levels below the reference range can be seen in hypoparathyroidism, kidney failure, vitamin D deficiency, and several other conditions.
- Talk with your health care provider about what your results may mean.
