My endocrinologist suspects hyperparathyroid. She just did a blood test of PTH without calcium. It was 22. Is this a normal test and result? I had other labs showing calcium of 10.5 mg/dl and PTH 88 pg/ml. I am 65 years old.
The parathyroid hormone (PTH) level you mentioned (22 pg/ml) falls within the normal range, which is typically between 10 to 65 pg/ml. However, we cannot interpret PTH levels without calcium levels. A “normal range” PTH is only normal if the calcium level is also normal.
The parathyroid glands produce PTH in order to regulate the amount of calcium in our blood. If your calcium level is low, then normal parathyroid glands will make more PTH in order to bring the calcium up. If your calcium goes too high (over 10.0 mg/dl for adults over age 40), then normal parathyroid glands will shut down hormone production and your PTH should be in the low range (around 20 pg/ml or lower).
In primary hyperparathyroidism, typically the calcium will be high, but the PTH level will not be suppressed - it will be in the high or “normal” range.
In your case, you mentioned that your calcium level was 10.5 mg/dl (which is high for your age) and your PTH level was 88 pg/ml (which is also high). These labs indicate primary hyperparathyroidism. The PTH of 22 is less convincing, so if all of your other labs show normal calcium levels (in the 9s mg/dl), then it could be that the prior labs were a mistake. On the other hand, if you have multiple calcium levels above 10.0, then it is very likely primary hyperparathyroidism. PTH levels can fluctuate with primary hyperparathyroidism - so high one day and normal the next. Calcium levels can fluctuate as well, though typically you should see multiple results with elevated calcium levels.
