I am a 35 yr old female with osteoporosis. (T-score is -3.8). I have many other symptoms of paraythyroid disease. I recently had a serum Ca that was only 9.3 (range: 8.4-10.2), but my IONIZED calcium was 1.3 (range: 1.16-1.32). It was tested again the next week and it was 92 with an ionized ca of 1.28 and a serum Ca of 9.7. I also have elevated levels of 132 (high end of range 120). My vit d 25 hydroxy is 23 (range: 30-80). In the past, I have had serum Ca levels from 10-10.2 with a PTH of 36 and once I had an ionized Ca at 5.7 (high end of range was 5.6) with a PTH at 50 (not checked the same day, but a week apart). My doc always tries to give me Vit D because he says it is secondary HPT, but I cannot tolerate Vit D because my get worse (serious fatigue, etc) every time I take it in small or large doses. I am not sure if my blood samples were handled properly, as I understand ionized ca needs to be spun, frozen immediately or the levels will start to drop. Since my recent ionized ca was high normal and the PTH is so high, do you think this might be consistent with parathyroid disease? Is it possible to have PHPT with only high normal ionized and normal serum ca and elevated PTH levels? Any help is appreciated!