khan is in the emergency room, complaining of severe back pain and pain when trying to urinate. the physician has ordered blood tests and urinalysis to measure levels of parathyroid hormone (pth) and phosphates. i. what possible reason would the physician have for doing this? ii. what would the physician conclude if the results of the blood test show high levels of pth and calcium and the urinalysis show high levels of phosphate? iii. how are calcium and phosphates related? iv. what is the physiological mechanism at work here?