Hormones
Parathyroid Hormone (PTH)
Also known as: Parathormone, Parathyrin, iPTH, Intact PTH
CONVERT & COMPARE
pg/mL
=
4.21
pmol/L
=
40
ng/L
Reference ranges by source
Published adult intervals: 4, from 4 named sources, shown in pg/mL.
SOURCE
SEX
AGE
RANGE
VISUAL
CITE
About Parathyroid Hormone (PTH)
This test measures the level of parathyroid hormone (PTH) in your blood. PTH is made by your parathyroid glands. They are four pea-sized glands in your neck.
Hormones are chemical messengers in your bloodstream. They control the actions of certain cells or organs. PTH controls the level of calcium in your blood. Calcium is one of the most important minerals in your body. Most of it is stored in your bones and teeth. Having the right amount of calcium in your blood is important for your nerves, muscles, and heart to work properly.
If your calcium blood levels are too low, your parathyroid glands will release just enough PTH into your blood to return your calcium levels to normal. When your calcium blood levels return to normal, your parathyroid glands stop making PTH and your blood PTH levels decrease.
Main source: MedlinePlus ↗
Useful for
Help find out whether parathyroid disorders are the cause of abnormal blood calcium levels. This is the most common use.
Help find the cause of abnormally low results on a phosphate blood test. That's because PTH also helps control the amount of phosphate (phosphorus) in blood.
Monitor people with chronic kidney disease.
Help find the cause of severe osteoporosis, a condition that causes your bones to become weak and break easily.
Check whether treatment for a known parathyroid disorder is working.
Check whether all overactive parathyroid tissue has been removed during surgery to treat parathyroid disorders that cause too much PTH.
Main source: MedlinePlus ↗
Interpretation
Many health conditions can cause abnormal PTH levels. To understand what your PTH test results mean, your provider will consider the results of other tests, especially a blood calcium test. Your symptoms, medical history, and family history will also be considered.
If your PTH level is higher than normal, it's called hyperparathyroidism. The type you have generally depends on your blood calcium level.
Secondary hyperparathyroidism is high PTH levels with low blood calcium levels. Your parathyroid glands are working correctly by making extra PTH to try to increase your blood calcium. It's likely that a problem outside of your parathyroid glands is preventing your blood calcium levels from increasing.
Your provider will probably order more tests to find out what's causing your low blood calcium.
For general wellness information only. Talk to a clinician about your specific results.
Main source: MedlinePlus ↗
Track your parathyroid hormone (pth) in MyBloodTest
Save reviewed lab results and follow their history. Scanning requires sign-in and has plan-specific limits.
Open the web app
iOS · Android · Web
Related biomarkers
More tests in the hormones category.
Sources
Last updated 2026-05-02
This page presents source-specific reference data and sourced explanations. For general wellness information only. This is not medical advice. For diagnosis or treatment of any condition, talk to a qualified clinician.