At a Glance
Why Get Tested?
To determine the cause of calcium imbalances; to evaluate parathyroid function; to diagnose and differentiate between primary, secondary, and tertiary hyperparathyroidism; to diagnose hypoparathyroidism; during surgery for hyperparathyroidism to confirm removal of the gland(s) causing the problem
When to Get Tested?
When calcium blood levels are higher or lower than normal; when you are having surgery for hyperparathyroidism; when your health practitioner wants to determine how well your parathyroid glands are functioning
A blood sample drawn from a vein in your arm
Test Preparation Needed?
Current practices do not require fasting.
PTH levels peak during sleep hours and are lowest during mid-morning to late afternoon hours, the period when most samples are drawn. There may be seasonal fluctuations in PTH due to its inverse relationship with vitamin D. Talk to your health practitioner about sample timing.