A calcium test is a blood test that measures the amount of calcium in your blood. Calcium is an essential mineral that plays important roles in bone health, muscle contraction, nerve function, blood clotting, and heart rhythm regulation.

What the calcium test measures

There are two main types of calcium tests:

• Total Calcium: Measures both the calcium that is attached to proteins (mainly albumin) and the free calcium circulating in the blood.

• Ionized Calcium: Measures the active form of calcium that is not bound to proteins and is available for the body to use.

What abnormal calcium levels may indicate

High calcium levels (hypercalcemia) may be associated with:

• Overactive parathyroid glands (hyperparathyroidism)

• Certain cancers

• Excess vitamin D intake

• Some medications

• Dehydration

• Certain bone disorders

Low calcium levels (hypocalcemia) may be associated with:

• Vitamin D deficiency

• Low parathyroid hormone levels

• Kidney disease

• Magnesium imbalance

• Malabsorption disorders

• Certain medications

What the calcium test can help evaluate

Healthcare providers may order a calcium test to:

• Assess bone and mineral health

• Evaluate symptoms such as muscle cramps, weakness, tingling, confusion, or abnormal heart rhythms

• Monitor kidney disease

• Evaluate parathyroid gland function

• Monitor certain cancers or treatments

• Check calcium balance as part of a metabolic panel