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Parathyroid Hormone (PTH) Test: Normal Range Explained

What PTH controls in your body, normal reference ranges, and what abnormal results can indicate.

Written and clinically reviewed by Suman Konda, PharmD, Clinical Pharmacist · Based on peer-reviewed sources · Editorial policy · Not medical advice

Last reviewed and updated: · How we check our content

What Is Parathyroid Hormone?

PTH is produced by four small parathyroid glands in your neck. It regulates calcium, phosphorus and vitamin D levels in your blood and bones.

Normal PTH Range

TestNormal Range
Intact PTH10–65 pg/mL
Calcium (paired test)8.5–10.5 mg/dL

What High PTH Means

Primary Hyperparathyroidism

One or more parathyroid glands overproduce PTH, usually from a benign tumour, raising blood calcium and weakening bones.

Secondary Hyperparathyroidism

Glands overproduce PTH in response to low calcium, often from kidney disease or vitamin D deficiency.

What Low PTH Means

Hypoparathyroidism can result from gland damage during neck surgery, autoimmune disease or genetic conditions, leading to low calcium and symptoms like muscle cramps and tingling.

Symptoms of Abnormal PTH

  • Bone pain or fractures
  • Kidney stones
  • Fatigue and weakness
  • Muscle cramps or tingling (low calcium)
  • Excessive thirst and urination (high calcium)

Frequently Asked Questions

Why is PTH always checked alongside calcium?
PTH and calcium must be interpreted together. High calcium with high PTH points to primary hyperparathyroidism, whereas high calcium with low PTH suggests another cause such as cancer: the pairing is what makes the diagnosis.
What causes a high PTH level?
Common causes include primary hyperparathyroidism (an overactive parathyroid gland), vitamin D deficiency, and chronic kidney disease, where PTH rises to compensate for disturbed calcium and phosphate balance.
Can low vitamin D raise my PTH?
Yes. Low vitamin D reduces calcium absorption, prompting the parathyroid glands to release more PTH (secondary hyperparathyroidism). Correcting the vitamin D deficiency often brings PTH back down.

Interpreting PTH alongside calcium

PTH is almost never interpreted alone: it only becomes meaningful when read together with the calcium level taken at the same time. Four broad patterns are recognised, and each points in a different direction.

High calcium with high or inappropriately normal PTH indicates primary hyperparathyroidism, usually from a benign parathyroid adenoma. High calcium with suppressed PTH suggests a non-parathyroid cause such as malignancy. Low calcium with high PTH is the expected compensatory picture in vitamin D deficiency or chronic kidney disease. Low calcium with low PTH points to hypoparathyroidism, often following thyroid or parathyroid surgery.

References

The clinical information on this page is drawn from peer-reviewed sources indexed by the US National Library of Medicine. Links go to the source so you can read it yourself.

  1. Primary Hyperparathyroidism. In: StatPearls. Treasure Island (FL): StatPearls Publishing. NCBI Bookshelf NBK441895

Related reading

Important: PTH is usually interpreted together with calcium, phosphorus and vitamin D levels. Discuss abnormal results with your doctor or an endocrinologist.