Parathyroid Hormone (PTH)
Measures parathyroid hormone levels to assess calcium regulation and diagnose parathyroid gland disorders.
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What this test measures
Parathyroid hormone (PTH) is a hormone your parathyroid glands release to control calcium levels in your blood. PTH also helps control the levels of phosphorus (a mineral) and vitamin D (a hormone) in your blood and bones. Your parathyroid gland releases parathyroid hormone (PTH) when your body detects low calcium levels in your blood.
PTH raises your blood calcium by telling your bones to release calcium into your blood, helping your intestines to absorb calcium from the food you eat, and helping your kidneys to keep calcium in your blood instead of getting rid of it through your urine. The PTH test measures the level of this hormone in the blood to help healthcare providers diagnose conditions affecting calcium balance, bone health, and parathyroid gland function. This test is particularly valuable because calcium regulation is essential for proper nerve, muscle, and heart function.
Who should consider this test
You might consider this test if you are experiencing any of the following:
- Individuals with abnormal calcium levels discovered on routine blood tests may need PTH testing to determine if parathyroid glands are functioning properly.
- Those experiencing symptoms of high calcium levels, such as fatigue, nausea, abdominal pain, kidney stones, or bone pain, should consider this test to evaluate potential hyperparathyroidism.
- Patients with symptoms of low calcium levels, including muscle cramps, tingling in fingers and toes, or muscle spasms, may benefit from PTH testing to assess for hypoparathyroidism.
- People with chronic kidney disease often require regular PTH monitoring as kidney dysfunction can affect calcium and phosphorus balance, leading to secondary hyperparathyroidism.
- Individuals with osteoporosis or unexplained bone loss may need PTH testing to rule out parathyroid disorders as an underlying cause of their bone health issues.
- Those with a family history of parathyroid disorders or multiple endocrine neoplasia syndromes should consider testing if they develop relevant symptoms.
What to expect
Preparation
No fasting is required for this test. Morning collection is often preferred as PTH levels can fluctuate throughout the day. Patients should inform the lab of any medications they are taking, particularly calcium or vitamin D supplements, as these may affect results.
Sample Type
A simple blood draw from a vein in the arm, typically taking less than five minutes. The blood is collected in a special tube and must be handled carefully as PTH is unstable at room temperature.
Collection
The healthcare provider will clean the injection site, insert a small needle to draw blood, and collect the sample in appropriate tubes. Patients may feel a brief pinch when the needle is inserted.
Turnaround
Results are typically available within 1-3 business days after the sample reaches the laboratory.
Understanding your results
The normal range for a PTH blood test is 15 to 65 picograms per milliliter (pg/mL), though this may vary slightly between laboratories. PTH results must be interpreted alongside calcium levels for accurate diagnosis.
| Population | Reference Range | Notes |
|---|---|---|
| Adults | 15-65 pg/mL | Most commonly reported range, though some labs use 10-65 pg/mL |
Reference ranges may vary by laboratory and individual factors. Results should be interpreted by a healthcare provider in the context of your overall health.
What does a “Low” result mean?
If PTH levels are lower than normal and blood calcium level is also low, it may mean parathyroid glands can't make enough PTH. This is called hypoparathyroidism. About 3 out of 4 cases (75%) are from accidental damage to parathyroid glands from neck or thyroid surgery. Low PTH levels can also occur with certain genetic conditions or autoimmune disorders affecting the parathyroid glands.
What does a “High” result mean?
If PTH level is higher than normal, it's called hyperparathyroidism. Primary hyperparathyroidism is high PTH levels with high blood calcium levels, often meaning that a problem with parathyroid glands is causing them to make too much PTH. The most common cause is a benign tumor (not cancer) in one of the parathyroid glands, called a parathyroid adenoma. Secondary hyperparathyroidism may occur when PTH levels are high but calcium levels are low, often due to vitamin D deficiency, kidney disease, or malabsorption disorders.
Privacy & confidentiality
All PTH test results are completely confidential and protected under HIPAA regulations. Results are not shared with insurance companies or added to your medical records without your consent, and no insurance billing occurs with direct-pay testing.
Frequently asked questions
Related tests
Calcium
$29Essential companion test to PTH as calcium and PTH levels must be interpreted together
View TestVitamin D
$59Vitamin D deficiency can cause secondary hyperparathyroidism and affects calcium absorption
View TestPhosphorus
$29PTH regulates phosphorus levels, and phosphorus testing helps complete the bone metabolism picture
View TestMagnesium
$39Magnesium deficiency can impair PTH function and affect calcium metabolism
View TestRelated conditions
CPT Code: 83970
This test may not be available in: NY, NJ, RI
This page is for informational purposes only and does not constitute medical advice. Always consult with a healthcare provider regarding any health concerns. LevelPanel does not diagnose, treat, or prescribe.
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