Thanks for writing. Low Vitamin D levels are associated with primary hyperparathyroidism, but do not diagnose it. The diagnosis of primary hyperparathyroidism relies mostly on calcium and PTH levels. Sometimes Vitamin D levels can help support the diagnosis (or point away from it). But with calcium and PTH levels in the true normal range, Vitamin D does not play a big role in the diagnosis of primary hyperparathyroidism.

While your symptoms and kidney stones certainly suggest the possibility of primary hyperparathyroidism, your labs point away from that. Your calcium levels are perfect - most adults should be in the mid to high 9s. PTH levels in the 40s are also perfect, and do not indicate any problems with your parathyroids.

Your Vitamin D 25-OH is on the low end, and the 1,25 is on the high end. While this pattern is seen in parathyroid disease, that does not seem to be the cause for you. I cannot explain why you feel much worse when you take Vitamin D. Sometimes the additives in vitamins are what cause these reactions, not the vitamin itself. Fortunately your body can make Vitamin D if your skin is exposed to sunlight. I would recommend getting a little more sunlight. You don’t want to get a sunburn, but being outside and getting sunlight does raise your Vitamin D level naturally.

Because your clinical picture is a little unusual, I would recommend keeping an eye on your calcium levels. Sometimes they fluctuate, and we just happen to catch them on good days. If this is parathyroid disease, the labs will generally become more convincing with time.