Parathyroid Hormone (PTH) - Active, Intact
This test measures the active, intact form of parathyroid hormone, a key hormone that regulates calcium levels in your blood.
["Active PTH helps maintain healthy calcium and bone metabolism."]
Key facts at a glance
- LOINC
- 45190-6
- Short code
- CASR
- Synonyms
- CASR gene Mut Anl Bld/T
- Category
- chemistry
- Sample
- whole-blood
- Container
- EDTA (lavender-top) tube for whole blood; sterile container for tissue specimens
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- ≥ 0 years
- Method
- molgen
- CPT
- 81405
- SNOMED
- 5304004
- Specimen volume
- 3-5 mL whole blood in EDTA tube; minimum 1 mL for pediatric samples; 5-10 mg tissue
- Stability
- Whole blood: stable for 7 days at 2-8°C; long-term storage at -20°C or -80°C. DNA extracted from samples stable for years at -20°C. Tissue: stable in DNA preservative or frozen at -80°C indefinitely.
- Hemolysis max
- 0
- Lipemia max
- 0
- Icterus max
- 0
- TAT
- 168–720 hours
- Order
- routine
Why This Test Is Done
Your doctor may order this test to diagnose or monitor conditions affecting calcium balance, such as hypoparathyroidism (low PTH), hyperparathyroidism (high PTH), or kidney-related disorders. It may also be used to evaluate symptoms like bone pain, muscle weakness, or abnormal calcium levels in the blood.
What to Expect Before the Test
No special preparation is needed. You’ll provide a blood sample, typically drawn from a vein in your arm. If you’re on certain medications (like calcium supplements or vitamin D), your doctor may advise timing them around the test to avoid interference.
What the Results Mean
Results help determine if your PTH levels are too high or too low, which can indicate underlying health issues. While reference ranges vary by lab, abnormal results may prompt further testing or adjustments to treatment.
Common Conditions Linked to PTH Levels
High PTH levels may suggest hyperparathyroidism, while low levels could point to hypoparathyroidism. Other conditions like kidney disease, vitamin D deficiency, or certain cancers may also affect PTH levels.
Reference range
No mutations detected (Negative) is considered a normal result. The report will specify any identified CASR gene variants with classification (pathogenic, likely pathogenic, variant of uncertain significance, likely benign, or benign) according to ACMG guidelines.N/A
No special patient preparation is required. Patients should provide informed consent for genetic testing and disclose any relevant family history of calcium metabolism disorders.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Clinical Significance
Short name
PTH Active
Frequently asked questions
What causes abnormal PTH levels?
How long does it take to get results?
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.
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