Parathyroid Hormone (Active), Serum/plasma
This test measures the active form of parathyroid hormone (PTH), a key hormone that helps regulate calcium levels in your body.
["Active PTH helps your bones, kidneys, and intestines maintain healthy calcium and phosphorus balance."]
Key facts at a glance
- LOINC
- 33845-9
- Short code
- PTH-Intact 1h p chal SerPl-sCnc
- Synonyms
- PTH-Intact 1h p chal SerPl-sCnc
- 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 Is Done
Your doctor may order this test if you have symptoms like bone pain, frequent fractures, or unexplained high or low calcium levels. It may also be used to monitor conditions like hyperparathyroidism or hypoparathyroidism, or to check for kidney disease or metabolic bone disorders.
What to Expect Before the Test
No special preparation is usually needed. You may be asked to fast for 8–12 hours before the test if your blood is drawn early in the morning. Avoid calcium-rich foods/drinks for 24 hours before testing if instructed.
How the Test Is Performed
A healthcare provider will draw blood from a vein in your arm using a small needle. You may feel a slight pinch, but it usually doesn’t cause discomfort afterward.
What the Results Mean
Results are interpreted by your doctor based on your symptoms, medical history, and other test results. Abnormal levels may indicate conditions affecting calcium metabolism or bone health.
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.
◆Associated findings1
Short name
Active PTH
Frequently asked questions
High active PTH levels may suggest overactive parathyroid glands (hyperparathyroidism), which can lead to weakened bones, kidney stones, or heart issues. Low levels could indicate underactive glands (hypoparathyroidism) or other metabolic disorders.
This test is typically done in a lab and results are usually available within 1–3 business days. Follow-up testing may be needed if your results are outside the expected range.
No, active PTH is measured in serum or plasma, not urine. Your blood sample is sent to a lab for analysis.
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