Hormone Panel Updated Apr 17, 2026

Parathyroid Hormone (PTH)

Parathyroid Hormone (PTH) is a hormone measured in blood to show how much parathyroid signal is circulating at the time of the test. PTH on a lab report helps describe how the body is regulating calcium and related minerals. The result is often interpreted with other markers and the Parathyroid Hormone reference range for the same lab method.

What Is Parathyroid Hormone (PTH)?

Parathyroid Hormone (PTH) is a blood measurement of the parathyroid hormone level circulating in the sample. It is a chemical messenger made in the neck and released into blood, so a Parathyroid Hormone on a lab report reflects hormone activity rather than red cell traits or protein levels. The PTH test is usually reported as a concentration in picograms per milliliter (pg/mL).

Why Is Parathyroid Hormone (PTH) Tested?

The PTH test is used in hormone-focused lab panels and in workups that also review calcium, phosphorus, and vitamin D-related values. A Parathyroid Hormone on a blood test helps show how the body is regulating mineral balance over time. It is most useful when read with serum calcium, phosphate, magnesium, and albumin, rather than by itself. In routine reporting, the full name Parathyroid Hormone and the abbreviation PTH may both appear on the lab report.

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Parathyroid Hormone (PTH) Normal Range

Group Range Unit
Adult Male 15–65 pg/mL
Adult Female 15–65 pg/mL

Reference ranges may vary by laboratory and individual factors.

What Does High PTH Mean?

High PTH means the measured hormone level is above the lab’s Parathyroid Hormone normal range, often above about 65 pg/mL in many adult reference methods. A high PTH result generally reflects increased hormone output or reduced clearance of the hormone in blood. On a Parathyroid Hormone test result, this can show a stronger signal for calcium regulation than expected for that sample. The exact cutoff for high PTH depends on the assay used by the laboratory.

Associated factors

Low calcium intake — less calcium exposure can increase PTH release to keep blood calcium stable.
Vitamin D intake changes — lower vitamin D availability can raise PTH because less calcium is absorbed from food.
Dehydration — reduced plasma volume can concentrate the measured PTH in the blood sample.
Reduced kidney clearance — slower removal of PTH can increase the circulating level.
Certain medicines — some medications can shift calcium handling and change PTH output.
Age-related variation — PTH tends to run higher in some older adults compared with younger adults.
Sex hormone changes — shifts in estrogen or testosterone levels can influence PTH balance.
Physical stress or intense exercise — temporary changes in blood minerals can move PTH upward.
Low magnesium intake — magnesium affects calcium signaling and can increase PTH release.

What Does Low PTH Mean?

Low PTH means the measured hormone level is below the lab’s Parathyroid Hormone normal range, often below about 15 pg/mL in many adult reference methods. A low PTH result generally reflects reduced hormone release or a smaller circulating amount in blood. On a Parathyroid Hormone on a lab report, low PTH is interpreted together with calcium and phosphate values. The exact cutoff for low PTH depends on the laboratory method and specimen handling.

Associated factors

High calcium intake — more available calcium can suppress PTH release.
Magnesium excess — higher magnesium can reduce PTH secretion in some settings.
Recent food and supplement use — calcium or vitamin D supplements can shift the measured PTH level.
Certain medicines — some drugs can reduce PTH release or alter calcium balance.
Sample timing — time of day can affect PTH because the hormone changes across the day.
Hydration changes — higher plasma volume can dilute the measured hormone level.
Age-related variation — some groups have lower average PTH than others.
Pregnancy-related shifts — expanded blood volume and mineral changes can lower the measured concentration.
Lab handling factors — delayed processing can change measured PTH in the sample.

How Parathyroid Hormone (PTH) Relates to Other Values

PTH is usually read with calcium, phosphate, magnesium, and albumin. Calcium and PTH move in a linked pattern, so a Parathyroid Hormone test result is more informative when the calcium value is known. Phosphate and magnesium help show whether the mineral balance pattern fits a high PTH or low PTH pattern. Albumin matters because it can affect how total calcium is reported, which changes how the PTH result is interpreted.

What Factors Affect Parathyroid Hormone (PTH) Levels?

PTH varies by time of day, with modest shifts between morning and later samples. Hydration status can change the concentration in the blood sample, especially when plasma volume changes. Diet, calcium intake, vitamin D intake, and recent supplements can influence the Parathyroid Hormone reference range seen in practice. PTH can also differ by age, sex, pregnancy status, and the lab method used for the assay. In some populations, altitude and long-term lifestyle patterns may also affect the typical Parathyroid Hormone normal range.

How It Is Tested

The PTH test is done with a standard blood draw, usually from a vein in the arm. The lab measures intact parathyroid hormone in the sample and reports it in picograms per milliliter (pg/mL). A Parathyroid Hormone on a blood test may be sent as a routine chemistry add-on or as a separate hormone assay.

How to Prepare

No fasting is usually required for a PTH test, unless another ordered test needs it. Because specimen handling can matter, the lab may process the sample quickly after collection.

Frequently Asked Questions

What is a normal PTH level?
A normal PTH level is commonly about 15 to 65 pg/mL for many adult lab methods, but the Parathyroid Hormone reference range can vary by laboratory. The PTH result should be read using the range printed on the lab report. Different assay methods can shift the numeric interval.
What does PTH stand for?
PTH stands for parathyroid hormone. It is the abbreviation used on a PTH test and on many lab reports. The full name may appear as Parathyroid Hormone or simply PTH.
What does a high Parathyroid Hormone mean on a lab report?
A high PTH lab report value means the result is above the lab’s normal Parathyroid Hormone range. In general, high PTH reflects increased hormone signaling or less efficient clearance of the hormone in blood. The exact meaning depends on the paired calcium and phosphate values.
What does a low Parathyroid Hormone mean on a lab report?
A low PTH result means the measured value is below the lab’s normal Parathyroid Hormone range. In general, low PTH reflects reduced hormone release or a diluted sample concentration. It is best interpreted with calcium and magnesium.
Can hydration affect Parathyroid Hormone?
Yes, hydration can affect PTH in a small way because blood volume changes can slightly concentrate or dilute the measured result. A PTH test is still mainly interpreted with other mineral values. Large fluid shifts can make the number move between tests.
What is the difference between Parathyroid Hormone and calcium?
Parathyroid Hormone is a hormone measured in pg/mL, while calcium is a mineral usually measured in mg/dL or mmol/L. PTH helps regulate calcium, so the two values are often reviewed together on a blood test. A high or low PTH result is easier to understand when calcium is also known.
What unit is Parathyroid Hormone measured in?
PTH is usually measured in picograms per milliliter, written as pg/mL. Some laboratories may format the Parathyroid Hormone test result slightly differently, but pg/mL is the most common unit. The unit should be read with the lab’s reference range.
How much can Parathyroid Hormone change between tests?
PTH can change from one test to another because it varies with time of day, calcium intake, hydration, and lab method. Small differences are common, even when the overall pattern is similar. Larger changes are more meaningful when they move outside the normal PTH range.
Is Parathyroid Hormone different for men and women?
PTH can be similar for men and women, and many laboratories use the same adult reference interval for both. Some population averages may differ slightly by age and sex. The lab report’s own Parathyroid Hormone normal range is the best comparison point.
Why is Parathyroid Hormone tested in a hormone panel?
PTH is tested in a hormone panel to show how the body is handling calcium-related signaling. The PTH test is often reviewed with calcium, phosphate, magnesium, and albumin. That combination gives a broader picture than PTH alone.
What does PTH mean on a blood test?
On a blood test, PTH means parathyroid hormone in the blood sample. It is a marker of hormone activity that helps show how mineral balance is being regulated. The result is read against the lab’s reference range, not as a stand-alone number.

Disclaimer

This content is for informational and educational purposes only. It is not intended as medical advice, diagnosis, or treatment recommendation. Reference ranges may vary by laboratory. Always discuss your results with a qualified healthcare professional.

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