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 to maintain healthy blood calcium.
["Active PTH helps balance calcium and phosphate, critical for bone health and nerve function."]
Key facts at a glance
- LOINC
- 24346-9
- Short code
- PTH-Intact + Ca Pnl SerPl
- Synonyms
- PTH-Intact + Ca Pnl SerPl
- Category
- electrolyte
- 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 diagnose or monitor conditions such as hypoparathyroidism, hyperparathyroidism, or kidney disease that affect calcium metabolism.
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 blood. If you’re on blood thinners, let your doctor know before the test.
What the Results Mean
Results help determine if your PTH levels are too high or too low, which can indicate underlying health issues. Your doctor will compare your results to standard ranges and consider your symptoms and medical history.
Common Conditions Linked to PTH Levels
High PTH levels may suggest overactive thyroid glands (hyperparathyroidism), while low levels could indicate underactive thyroid glands (hypoparathyroidism). Kidney disease or certain medications can also affect PTH levels.
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.
PTH plays a vital role in regulating calcium and phosphate in your blood. When levels are abnormal, it can lead to complications like weak bones, heart problems, or nerve damage. Your doctor will use these results to guide treatment if needed.
Short name
PTH (Active)
Frequently asked questions
How often should I get this test?
What does an abnormal result mean?
Can diet or supplements 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