Calcium albumin corrected
The test measures the amount of calcium and Albumin in blood.
It is important to correct the amount of calcium with the albumin measurement.
See this calculator for this and order Albumin in addition if it is not already in your package.
There is also a lot of calcium in bones, but this test only says something about the amount of calcium in the blood. Urine measures the amount of calcium that leaves the body through the kidneys.
The amount of calcium in the blood is maintained by the parathyroid hormone parathormone (PTH) and vitamin D. When calcium is in danger of getting too low, production of PTH increases, releasing calcium from the bones. The kidneys start producing vitamin D which in turn causes calcium to be better absorbed from the intestines.
When calcium in the blood threatens to become too high, the production of PTH is reduced, creating a balance in production and requirement of calcium in blood.