A calcium blood test can determine if you have the right amount of calcium in your bloodstream. It’s often part of a regular health check-up. This test helps identify problems with your bones, heart, muscles, nerves, kidneys, and other organs. Most of your body's calcium is stored in your bones, but a small amount is in your blood. There are two types of blood calcium tests. Your doctor might do this test during a regular health exam or if you have a condition that affects calcium levels. It can also monitor treatment effects and medication side effects. Symptoms of high calcium include fatigue and nausea, while low calcium can cause muscle cramps. Some medicines might affect the test, so inform your doctor about all medications you're taking. The test involves taking a blood sample from your arm. Results typically come back in a few days. Normal calcium levels vary slightly by lab, so discuss your results with your doctor.