Parathyroid Hormone (Active), Serum
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 functioning properly.
["Active PTH helps balance calcium, which is vital for muscle, nerve, and bone health."]
Key facts at a glance
- LOINC
- 108803-8
- Short code
- PTH-Intact Msmt SerPl
- Synonyms
- PTH-Intact Msmt SerPl
- 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, muscle weakness, or unexplained kidney stones. It’s also used to monitor conditions like hypoparathyroidism or hyperparathyroidism, or to check for calcium imbalances.
What to Expect Before the Test
No special preparation is needed. You’ll have a small needle inserted into your arm or hand to draw a blood sample. The process takes a few minutes, and you may feel a brief pinch. Avoid eating or drinking for 8–12 hours before the test if instructed.
What the Results Mean
Results help determine if your PTH levels are too high or too low, which can affect calcium metabolism. High levels may suggest overactive thyroid glands, while low levels could indicate underactivity or other health issues.
Common Conditions Linked to PTH Levels
Abnormal PTH can be linked to conditions like osteoporosis, kidney disease, or vitamin D deficiencies. It’s also important for diagnosing rare disorders affecting calcium balance.
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.
Clinical significance: PTH is essential for maintaining calcium and phosphate levels in your blood. High levels may indicate overproduction by the parathyroid glands, leading to conditions like hypercalcemia. Low levels can cause hypocalcemia, affecting nerves, muscles, and bones. Regular monitoring helps manage these imbalances.
Short name
PTH (Active)
Frequently asked questions
What causes abnormal PTH levels?
How often should I get this test?
Can diet affect PTH test results?
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