Kidney & Electrolytes

Parathyroid Hormone (PTH) Test -- Calcium Regulation Marker

PTH is produced by the four parathyroid glands located behind the thyroid. When blood calcium drops, the parathyroids release PTH to mobilise calcium from bones, increase calcium reabsorption in the kidneys, and stimulate vitamin D activation for better intestinal absorption. Conversely, when calcium is high, PTH secretion is suppressed. Measuring PTH alongside calcium and phosphate helps diagnose parathyroid disorders, vitamin D deficiency, and chronic kidney disease.

Why Test Parathyroid Hormone, PTH?

A PTH test is recommended when calcium levels are abnormal, when parathyroid dysfunction is suspected, or when evaluating bone health, vitamin D status, or kidney disease. It is essential for distinguishing between the many causes of high or low calcium and for guiding treatment of conditions like osteoporosis.

What Do High Parathyroid Hormone, PTH Levels Mean?

Elevated PTH (hyperparathyroidism) can be primary -- caused by a parathyroid adenoma or hyperplasia -- or secondary, in response to low calcium, vitamin D deficiency, or chronic kidney disease. High PTH increases bone resorption, raises blood calcium, and can lead to kidney stones and weakened bones over time.

What Do Low Parathyroid Hormone, PTH Levels Mean?

Low PTH (hypoparathyroidism) may result from surgical damage to the parathyroid glands, autoimmune destruction, or magnesium deficiency. It leads to low blood calcium and high phosphate, which can cause muscle cramps, numbness, and tingling.

Symptoms to Watch For

  • Bone pain or tenderness
  • Muscle cramps or spasms
  • Fatigue and weakness
  • Kidney stones
  • Numbness or tingling in the hands and feet
  • Depression or cognitive difficulty

Who Should Get Tested?

  • People with abnormal calcium levels
  • Those with suspected parathyroid disorders
  • Patients with chronic kidney disease
  • Individuals with osteoporosis or unexplained bone loss
  • Anyone with vitamin D deficiency and persistent calcium issues

How to Prepare for Your Test

No special preparation is required. Bring a valid ID. Morning sampling may be preferred as PTH follows a circadian rhythm.

Order Your Blood Test

Test your Parathyroid Hormone, PTH levels with an accredited Swedish laboratory. Results within days, reviewed by Wellth.

Parathyroid Hormone (PTH) →

Frequently Asked Questions

What is the relationship between PTH and calcium?
PTH raises blood calcium when levels are low by releasing calcium from bones, reducing calcium loss through the kidneys, and increasing calcium absorption from food via vitamin D. When calcium is adequate, PTH secretion decreases.
Can kidney disease affect PTH?
Yes. In chronic kidney disease, the kidneys cannot activate vitamin D or excrete phosphate efficiently. This leads to low calcium and chronically elevated PTH -- a condition called secondary hyperparathyroidism.
How is PTH different from phosphate?
PTH is a hormone that regulates both calcium and phosphate. Phosphate is a mineral. PTH raises calcium and lowers phosphate. Testing both helps your doctor understand the full metabolic picture.
Should PTH be tested together with other markers?
Yes. PTH is most informative when interpreted alongside calcium, phosphate, vitamin D, and kidney function tests. This combination allows accurate diagnosis of parathyroid and metabolic bone disorders.
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Wellth Team

Wellth

Our content is written and reviewed by Wellth, and fact-checked against peer-reviewed research and current Swedish clinical guidelines.

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Medical Disclaimer

The information on this page is provided for informational purposes only and does not constitute professional medical advice, diagnosis, or treatment. Wellth provides health information and testing services but is not a substitute for clinical care. Always consult a qualified healthcare provider if you have questions about a medical condition. If you are experiencing severe or urgent symptoms, contact your doctor or call 1177 Vårdguiden. Blood test results should be interpreted by a qualified healthcare professional in the context of your complete medical history.