Parathyroid hormone test
Also called: PTH test, PTH, parathyroid hormone
What it means
A parathyroid hormone (PTH) test measures the amount of PTH in your blood, usually alongside calcium, to help find correctable causes of bone loss.
A high-normal calcium with a high PTH can point to primary hyperparathyroidism, a genuinely reversible cause of bone loss, so catching it can change your treatment path.
Parathyroid hormone is released by your parathyroid glands whenever blood calcium drops too low. It acts as a signal to osteoclasts, telling them to break down bone so calcium can be released into the bloodstream. This is a normal part of how your body protects blood calcium levels, even if it means borrowing from your bones to do it.
A PTH test is usually checked together with calcium, because the pattern of the two results together tells a story that neither does alone. A high-normal calcium paired with a high PTH is how primary hyperparathyroidism typically shows up, and this is important because it is a genuinely reversible cause of bone loss. This test is one of a short list, alongside vitamin D, thyroid function, kidney function and magnesium, that helps explain correctable causes of bone loss.
If bone loss has no obvious explanation, asking your physician whether a correctable cause has been ruled out, including checking PTH and calcium, is a reasonable question. These results are also worth recording alongside your scan results, vitamin D, and fracture history, since bone health is best understood as a trend over time rather than a single snapshot.
How sure is this?
Graded Strong Clinical Evidence: Supported by multiple well-designed clinical studies in humans. Read each study with its grade in mind. One study is a piece of the picture, not the whole of it.
Where the Academy teaches it
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Questions people ask about this
CTX and P1NP are blood tests that show how fast your bone remodeling is happening right now, rather than where your bone density stands. CTX reflects how quickly bone is being broken down, and P1NP reflects how quickly new bone is being built. Unlike a density scan, which takes a year or more to show change, these markers can shift within weeks to months, so they're useful for tracking your own trend over time.
Read the full answer →Related words
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Education only, not medical advice. Decisions about tests, medications and treatment belong with your own doctor. OsteoStrong does not diagnose, treat or cure any disease.
