PTH — The Hormone That Sets Your Calcium
Parathyroid hormone controls calcium, phosphorus and vitamin D in the blood. How to read your PTH result alongside the calcium measured in the same draw.
Parathyroid hormone (PTH) is released by the parathyroid glands and controls calcium, phosphorus and vitamin D levels in the blood, and plays a role in regulating bone. Because a PTH value only makes sense against the calcium it's regulating, a clinician measures blood calcium in the same draw.
The biomarker
- Name: Parathyroid Hormone (PTH)
- Units: pg/mL
- Standard reference range: about 10 to 65 pg/mL per the MedlinePlus encyclopedia (ranges vary by lab and assay)
How to read your result
| Value | Interpretation |
|---|---|
| Within your lab's range | No PTH question raised on its own — still read together with the calcium measured in the same draw |
| Below the range | Can let blood calcium fall — needs clinical interpretation |
| Above the range | Needs to be read against the calcium from the same draw, and with kidney function — discuss with a clinician |
What moves the needle
- Reading it. Always read PTH together with calcium measured in the same draw, and with phosphate and vitamin D.
- Trend. Keep earlier results — calcium and PTH moving together over time says more than one pair of values.
- If flagged. Ask the ordering clinician whether the pair should be repeated.
- Never. Do not start calcium or vitamin D supplements to "correct" a PTH result without clinical advice.
Why ask for it
- It is often ordered when calcium is abnormal or when kidney disease is being followed.
- A PTH in range can still be out of step with a high calcium — which is exactly why the two are read together rather than PTH alone.
Sources
AgeGen lab guides are educational only. We do not provide medical diagnosis, prescribe brands, or recommend specific doses. Talk to a licensed clinician before changing your supplement or medication routine.
