Parathyroid Hormone (Active), Serum
This test measures the active form of parathyroid hormone (PTH), a key hormone that helps regulate calcium levels in your body. It’s often checked if you have symptoms of low or high calcium or related conditions.
["Active PTH helps balance calcium and phosphate, influencing bone health and nerve function."]
Key facts at a glance
- LOINC
- 63302-4
- Short code
- PTH Ab Titr Ser IF
- Synonyms
- PTH Ab Titr Ser IF
- 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
- Method
- if
- 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
Your doctor may order this test to diagnose or monitor conditions like hypoparathyroidism (low PTH), hyperparathyroidism (high PTH), or kidney disease, which can affect calcium metabolism.
What to Expect Before the Test
No special preparation is needed. You’ll provide a blood sample, usually drawn from your arm. If you’re on blood thinners or have a history of bleeding disorders, let your doctor know.
What the Results Mean
Results help determine if your calcium levels are too high or too low, which can cause symptoms like muscle weakness, bone pain, or abnormal heart rhythms. Your doctor will interpret results in the context of your overall health.
Common Conditions Monitored
This test is used to evaluate conditions such as vitamin D deficiency, kidney disease, or metabolic bone diseases. It’s also checked after surgery involving the parathyroid glands.
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: Active PTH is crucial because it directly regulates calcium and phosphate levels. While total PTH can be measured, active PTH reflects the biologically active form that actually drives calcium absorption in the gut and bone resorption.
Short name
Active PTH (Serum)
Frequently asked questions
What is the difference between active and total PTH?
Can diet or supplements affect this test?
How often is this test repeated?
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