Parathyroid Hormone (Active), Serum/Plasma Concentration
This test measures the active (bioactive) form of parathyroid hormone (PTH) in your blood. PTH is a hormone that helps regulate calcium and phosphate levels in your body.
["Active PTH helps assess calcium metabolism and potential hyperparathyroidism or hypoparathyroidism."]
Key facts at a glance
- LOINC
- 33846-7
- Short code
- PTH-Intact 2h p chal SerPl-sCnc
- Synonyms
- PTH-Intact 2h p chal 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 This Test Might Be Ordered
Your doctor may recommend this test if you have symptoms like bone pain, frequent fractures, or unexplained kidney stones. It could also be done to monitor conditions like hypercalcemia (high calcium), hypocalcemia (low calcium), or kidney disease. Additionally, it may be used to check for overactive or underactive thyroid function or to evaluate metabolic bone diseases.
What to Expect Before the Test
No special preparation is usually needed. You may be asked to fast for 8–12 hours before the test if your doctor specifies it, but this is not always required for PTH. Bring any medications you’re taking to your appointment.
What Happens During the Test
A healthcare provider will draw blood from a vein in your arm. You may feel a small pinch, but it usually doesn’t cause discomfort. The blood sample is then sent to a lab for analysis.
What the Results Mean
Results help doctors determine if your PTH levels are too high (hyperparathyroidism) or too low (hypoparathyroidism), which can affect calcium balance and bone health. Abnormal results may guide treatment, such as medication or lifestyle changes.
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.
◆Associated findings1
Short name
Active PTH
Frequently asked questions
What causes abnormal PTH levels?
How long does it take to get results?
Can I eat or drink before this test?
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