Yes, it is common for PTH levels to fluctuate after parathyroid surgery, especially when the calcium drops down into the low-normal range after being elevated for so long.

Your calcium level is now in the low-normal range, which is a good sign. The PTH is high, but this is may be appropriate for your calcium. Your body was dealing with parathyroid disease for years, and you had a pretty high calcium prior to surgery. Given your very high PTH level, it is likely that you have lost calcium from your bones. Once the parathyroid tumor is removed, the calcium starts going back into the bones, and your blood calcium can drop into the low range. When that happens, the remaining parathyroid glands release PTH in order to bring the calcium back to normal. This is called secondary hyperparathyroidism.

The dose of calcium and Vitamin D you’re taking is usually a good amount, but since your calcium is on the low end and PTH is elevated, it looks like you need more. I would typically recommend taking around 1000 to 1200 mg of calcium daily in divided doses, as well as 2000 to 3000 units of Vitamin D daily.

At this point I would say that it is very likely that you are cured of primary hyperparathyroidism, but have developed some secondary hyperparathyroidism postoperatively. Again, secondary hyperparathyroidism occurs when the calcium level drops and the parathyroids make more PTH in order to get the calcium up.

After you have been on the higher doses of calcium and Vitamin D for a few months, I would recommend rechecking your levels. It is likely that the PTH will come down with increased supplementation.