Parathyroid Hormone (Active), Serum
This test measures the active form of parathyroid hormone (PTH) in your blood. PTH helps regulate calcium levels in your body and plays a key role in bone metabolism.
["Active PTH helps your body maintain healthy calcium and bone balance."]
Key facts at a glance
- LOINC
- 50527-1
- Short code
- PTH-Intact sp3 SerPl-mCnc
- Synonyms
- PTH-Intact sp3 SerPl-mCnc
- 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 to check for conditions affecting calcium metabolism, such as hypoparathyroidism (low PTH), hyperparathyroidism (high PTH), or kidney disease. It can also help diagnose or monitor conditions like pseudohypoparathyroidism or vitamin D deficiency.
What Does a High or Low Result Mean?
High levels of active PTH may indicate overactive parathyroid glands or conditions that reduce calcium absorption. Low levels could suggest underactive glands or other metabolic issues.
Sample Preparation
This test uses a blood sample drawn from a vein. You may feel slight discomfort, but it usually doesn’t cause lasting pain. Avoid eating or drinking for a few hours before the test if instructed.
Common Conditions Monitored
Active PTH is often checked in patients with symptoms like muscle weakness, bone pain, or frequent fractures, which may signal abnormal calcium or bone health.
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 is clinically significant because it reflects the biologically active form of PTH, which directly influences calcium metabolism and bone turnover. While total PTH is commonly tested, active PTH provides more precise insights into its functional role in conditions like chronic kidney disease or metabolic bone disorders.
Short name
Active PTH
Frequently asked questions
What triggers a PTH test?
How long does it take to get results?
Can diet 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