In this case study, “Amelia” is confused by a call from her doctor’s office about her blood calcium levels. When it comes to calcium, she is familiar with the adage that calcium is needed for strong bones and teeth, and so the idea that her blood could contain too much calcium seems absurd. Amelia is asymptomatic, but follow-up visits with her doctor reveal a benign parathyroid gland adenoma that is secreting excess parathyroid hormone. Students are asked to interpret laboratory data and to describe the mechanism underlying parathyroid hormone-dependent hypercalcemia. The case would be appropriate for use in undergraduate courses in human anatomy and physiology, human physiology, animal physiology, or endocrinology. The case could also be used in general biology or medical terminology courses depending on the depth of coverage of the relevant concepts and terms in those courses.