Intact PTH optimal range and reference range
Compiled by Alina Radu, founder of Sera, from the published sources below · Last reviewed November 9, 2026
Sera's bands for Intact PTH:
- Optimal 15 – 55 pg/mL (1.59 – 5.83 pmol/L); sufficient 15 – 65 pg/mL (1.59 – 6.89 pmol/L); out of range below 15 or above 65 pg/mL.
Evidence grade: Published reference interval. A band that primarily reflects a published adult laboratory or population reference interval. It is not necessarily applicable to every assay or laboratory.
All units
| Unit | Optimal | Sufficient | Out of range |
|---|---|---|---|
| pg/mL | 15 – 55 | 15 – 65 | below 15 or above 65 |
| pmol/L | 1.59 – 5.83 | 1.59 – 6.89 | below 1.59 or above 6.89 |
What the evidence says
The acceptable band is the adult reference interval used by Mayo Clinic Laboratories and Labcorp, 15 to 65 pg/mL; intervals differ between assays, so the reporting laboratory's own range takes precedence. Not interpretable without a calcium drawn at the same time. High PTH with high calcium suggests primary hyperparathyroidism; high PTH with low or normal calcium is usually secondary, most often to vitamin D deficiency or reduced kidney function; low PTH with low calcium suggests hypoparathyroidism. A PTH near the top of the range with a low vitamin D is the common functional finding, and it resolves with repletion rather than investigation. The narrower optimal band, ending at 55 pg/mL, is a functional target with no published support.
Assay: Results differ meaningfully between platforms and methods. Compare against the interval printed by the issuing laboratory before acting on a borderline value.
Sources
- PTH2 - Parathyroid Hormone, Serum: Clinical & Interpretive — Mayo Clinic Laboratories, 2026 · Laboratory / reference-interval sourceAdult reference values of 15 to 65 pg/mL. Matches Sera's sufficient upper edge of 65; Sera's lower edge of 5 is 10 pg/mL below it.
- Parathyroid Hormone (PTH), Intact — Labcorp, 2026 · Laboratory / reference-interval sourceInterpretation table read against calcium: intact PTH 15 to 65 pg/mL with calcium 8.6 to 10.2 mg/dL is normal; above 65 with high calcium is primary hyperparathyroidism; below 15 with low calcium is hypoparathyroidism.
What PTH (Parathyroid Hormone) — Intact measures
The hormone that raises blood calcium by acting on bone, kidney and gut, measured as the intact molecule.
Almost never interpretable alone — it has to be read against calcium drawn at the same time. High PTH with high calcium points at primary hyperparathyroidism; high PTH with low or normal calcium is usually secondary, most often to vitamin D deficiency or reduced kidney function. A PTH in the upper reference range alongside a low vitamin D is the common functional finding.