Calcium (Total)

Serum Calcium measures the total amount of calcium (bound to albumin and free/ionized) in the blood. Calcium is essential for bone health, muscle contraction, nerve signaling, and blood clotting. Levels are tightly regulated by parathyroid hormone (PTH) and vitamin D. Abnormal levels can indicate issues with the parathyroid glands, vitamin D status, kidney function, or certain cancers. Ionized calcium is the biologically active form and may be more accurate if albumin is abnormal.