Parathyroid Hormone (PTH) by Immunoassay (Serum)
This test measures your blood level of parathyroid hormone, a protein that helps regulate calcium and phosphorus in your body.
["PTH helps balance calcium, which is vital for bone health and nerve function."]
Key facts at a glance
- LOINC
- 44137-8
- Short code
- PT Hrt W RNC IV
- Synonyms
- PT Hrt W RNC IV
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Ref low
- 0.8
- Ref high
- 1.2
- Critical range
- — – 5 N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- pt
- CPT
- 85610
- SNOMED
- 396252006
- Specimen volume
- 5 mL
- Stability
- Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 4–24 hours
- Order
- routine
Why Is This Test Done?
Your doctor may order this test to check for conditions affecting calcium levels, such as hypoparathyroidism (low PTH), hyperparathyroidism (high PTH), or kidney disease. It can also help diagnose or monitor conditions like osteoporosis, rickets, or pseudohypoparathyroidism.
What Does the Test Measure?
PTH is a hormone produced by the parathyroid glands. It signals your bones to release calcium into your bloodstream and helps your kidneys remove extra phosphorus. Abnormal levels can indicate issues with calcium metabolism or gland function.
How Is the Test Performed?
A blood sample is taken from a vein in your arm. The sample is sent to a lab where it is analyzed using an immunoassay method to detect PTH levels.
What Are Common Causes of Abnormal Results?
Low PTH levels may be due to thyroid disease, kidney problems, or surgical removal of the parathyroid glands. High PTH levels could result from overactive parathyroid glands, kidney failure, or certain cancers.
Reference range
INR: 0.8-1.2 (warfarin: 2.0-3.0)N/A
Inform your healthcare provider if you are taking blood thinners. No special preparation required.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
This test is critical for diagnosing and managing conditions that disrupt calcium balance, helping doctors tailor treatments like vitamin D supplements, medications, or surgery to restore normal hormone levels.
Short name
PTH (Serum)
Frequently asked questions
What might cause my PTH levels to be too high or too low?
How often should I have this test?
Can lifestyle changes affect PTH levels?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.
This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy