Parathyroid Hormone (Active), Intact
This test measures the active, intact form of parathyroid hormone (PTH), a key hormone that helps regulate calcium levels in your body.
["Active intact PTH helps your doctor assess calcium balance and diagnose conditions like hypoparathyroidism or hyperparathyroidism."]
Key facts at a glance
- LOINC
- 47718-2
- Short code
- PTH-Intact 4h p Ca SerPl-mCnc
- Synonyms
- PTH-Intact 4h p Ca SerPl-mCnc
- Category
- electrolyte
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Ref low
- 4.5
- Ref high
- 12
- 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 Matters
PTH plays a critical role in maintaining healthy calcium and phosphate levels in your blood. Low or high levels can lead to serious health issues, such as bone disease, muscle weakness, or abnormal heart rhythms. This test specifically looks at the fully intact (unbroken) form of PTH, which is the biologically active version that directly affects calcium metabolism.
What to Expect Before the Test
No special preparation is needed for this blood test. You may have a small needle inserted into your arm to draw a blood sample. If you’re on blood thinners or have a history of bleeding issues, let your doctor know before the test.
What the Results Mean
Results help your doctor determine if your calcium levels are balanced or if there’s an underlying issue affecting PTH production. Abnormal results may prompt further testing or treatment to manage conditions like hypocalcemia (low calcium) or hypercalcemia (high calcium).
Common Conditions Linked to PTH Levels
High levels of active intact PTH might suggest hyperparathyroidism (overactive thyroid glands), while low levels could indicate hypoparathyroidism (underactive thyroid glands) or other conditions like vitamin D deficiency or kidney disease.
Reference range
Adult: 4.5-12.0 μg/dLN/A
Take your thyroid medication after the blood draw if applicable. No fasting required.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Short name
Active Intact PTH
Frequently asked questions
How often will I need this test?
Can diet or supplements affect this test?
What if my results are out of range?
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