Parathyroid Hormone (Active), Serum/Plasma Concentration
This test measures the active form of parathyroid hormone (PTH), a key regulator of calcium levels in your body. It helps assess whether your thyroid glands are producing enough PTH to maintain healthy calcium balance.
["Active PTH helps diagnose conditions affecting calcium metabolism and bone health."]
Key facts at a glance
- LOINC
- 14866-8
- Short code
- PTH-Intact SerPl-sCnc
- Synonyms
- PTH-Intact SerPl-sCnc
- 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
- 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 if you have symptoms like bone pain, frequent fractures, or unexplained fatigue. It’s also used to monitor conditions such as hypoparathyroidism, hyperparathyroidism, or kidney disease that can affect calcium levels.
What Does the Test Measure?
Active PTH is the biologically active form of the hormone that signals your bones to release calcium and your kidneys to retain it. Unlike total PTH, this test focuses on the fraction that directly influences calcium metabolism.
How Is the Test Performed?
A blood sample is drawn from a vein in your arm. The sample is sent to a lab where it’s analyzed using an immunoassay method to detect the active PTH concentration.
What Are Common Causes of Abnormal Results?
Low active PTH levels may indicate hypoparathyroidism, vitamin D deficiency, or certain medications. High levels could suggest hyperparathyroidism, kidney disease, or bone disorders.
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.
Active PTH plays a critical role in maintaining calcium and phosphate balance. Abnormal levels can lead to complications like osteoporosis, kidney stones, or abnormal heart rhythms. This test is essential for diagnosing and managing conditions affecting bone and mineral metabolism.
Short name
Active PTH
Frequently asked questions
What does an abnormal active PTH level mean?
How often should I get this test?
Can lifestyle changes affect active 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.
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Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy