Calcium Test - this test measures the total amount of calcium in the blood, including both bound and free calcium. This essential mineral plays a crucial role in bone health, muscle contraction, nerve function, and heart function. The test is used to evaluate parathyroid function, monitor conditions that affect calcium metabolism such as kidney disease, hyperparathyroidism, and bone diseases. Abnormal levels can indicate a range of issues, from vitamin D deficiency to serious kidney or parathyroid disorders.