Low calcium levels can occur after gastric bypass. Since most calcium in the blood stream is bound to protein, anyone who has protein deficiency after gastric bypass is likely to have a low total calcium level on standard blood tests. This does not mean necessarily mean that the functional level of calcium in the blood is low. The test should be repeated to check the ionized calcium level – this is the true marker of calcium deficiency. A complete assessment of calcium status also includes the parathyroid hormone level (PTH). This hormone becomes elevated when the blood concentration of calcium starts to drop. An elevated PTH associated with a normal or low-normal ionized calcium is an indicator of calcium deficiency.
If the ionized calcium level is low the patient should be take an oral preparation of calcium such as (Tums 500mg tabs, 4 tablets a day). Of course, it is often a recommendation that women over 40 add supplemental calcium to their diet to prevent eventual osteoporosis. Supplemental calcium despite a normal ionized calcium in this group would be reasonable, as long as too high a level of calcium – hypercalcemia – does not occur.