There is currently no device available to check your calcium levels at home. We provided a letter of support to Dr. Xuewei Wang for his ongoing research in this area. There are other researchers looking into at-home calcium devices as well.
One of the challenges with bringing an at-home device to market is that calcium is very sensitive, and quickly changes outside the body. In hospitals, calcium levels are drawn directly from a vein, while at home you would be doing a finger stick which exposes the blood to air. While researchers are looking for ways to adjust for the changes that occur when exposed to air, we are likely still several years away from an FDA-approved at-home calcium monitoring device.