237SJ....you are correct.....in certain metastatic secondaries in bone, calcium can "leak" into the blood stream but these metastasis do have a unique radiological appearance of bone destruction and appearance..........this would have been mentioned in the X-Ray report.
Yes, osteoporosis is usually diagnosed on a bone density scan but can also be considered on serum calcium levels.
Let me know when the blood results return and if there was any mention on the X-Ray of an osteolytic lesion or if it just mentioned "hairline fracture."