Hello, One of the more common causes of high blood calcium is Hyperparathyroidism, that's why your doctor asks for the parathyroid test. Hyperparathyroidism is an increase in parathyroid gland function, this condition is usually caused by a benign tumor of the parathyroid gland. There are other causes of high blood calcium, including Hyperthyroidism, and cancer. Both of them may cause weight loss. There're effective treatments for most of the diseases nowadays, even for cancer. So don't worry too much, and wait for the lab test result. All the best. HTQ