What this marker measures
PTH, calcium, and vitamin D form a small system: PTH responds to calcium, calcium depends on vitamin D, and the kidneys regulate all three. Clinicians almost always order these together when looking into mineral or bone-related questions.
High or low: what it can mean
High PTH
Elevated PTH can be seen with low calcium, vitamin D insufficiency, certain kidney patterns, or a parathyroid-driven response. It is interpreted in the context of calcium and vitamin D simultaneously — a single PTH number rarely settles the picture, and diagnosis usually requires confirmation and clinical context.
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Low PTH
Low PTH is less common and may be seen with high calcium or after parathyroid surgery. It is reviewed together with the wider mineral panel and clinical context.
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Frequently asked questions
What is PTH?
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Parathyroid hormone is produced by the parathyroid glands and regulates calcium and phosphorus balance in the body. It is often reviewed with calcium, vitamin D, phosphorus, magnesium, kidney markers, and clinical context.
What does PTH measure?
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PTH, calcium, and vitamin D form a small system: PTH responds to calcium, calcium depends on vitamin D, and the kidneys regulate all three. Clinicians almost always order these together when looking into mineral or bone-related questions.
What does high PTH mean?
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Elevated PTH can be seen with low calcium, vitamin D insufficiency, certain kidney patterns, or a parathyroid-driven response. It is interpreted in the context of calcium and vitamin D simultaneously — a single PTH number rarely settles the picture, and diagnosis usually requires confirmation and clinical context.
What does low PTH mean?
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Low PTH is less common and may be seen with high calcium or after parathyroid surgery. It is reviewed together with the wider mineral panel and clinical context.
Related biomarkers
Editorial note
LabTestly explains lab markers using plain-English educational content. Reference ranges may vary by laboratory and should be interpreted with a clinician.
Educational content · Editorially reviewed for clarity · Last updated
Common sources used for lab-test education
Not medical advice
This page is for general understanding only and does not replace medical advice from your clinician. Reference ranges can vary by laboratory, age, sex, pregnancy status, medications, and clinical context.