Parathyroid Hormone, Active (PTH) - Serum
This test measures the active form of parathyroid hormone (PTH) in your blood, which helps regulate calcium levels in your body.
["Active PTH helps balance calcium and phosphate, affecting bone health and nerve function."]
Key facts at a glance
- LOINC
- 63301-6
- Short code
- PTH Ab Ser Ql IF
- Synonyms
- PTH Ab Ser Ql 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 Is This Test Done?
Your doctor may order an active PTH test to check for conditions affecting calcium metabolism, such as hypoparathyroidism (low PTH), hyperparathyroidism (high PTH), or kidney disease. It can also help diagnose or monitor conditions like osteoporosis, kidney stones, or vitamin D deficiency.
What Does the Test Involve?
A blood sample is taken from a vein, usually in your arm. The sample is sent to a lab for analysis using a specialized immunoassay method to measure the active PTH level.
What to Expect Before the Test
No special preparation is needed for this test. You may eat and drink normally before the blood draw. If you are on certain medications that affect calcium or PTH, inform your healthcare provider before the test.
What Are Possible Results?
Results are interpreted by your healthcare provider based on your overall health, symptoms, and medical history. Abnormal results may indicate imbalances in calcium or PTH levels that need further evaluation.
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.
Active PTH is crucial for maintaining calcium homeostasis. Low levels may suggest hypoparathyroidism, while elevated levels can point to hyperparathyroidism or other metabolic disorders. Monitoring PTH levels helps manage conditions affecting bone density, kidney function, and nerve signaling.
Short name
Active PTH
Frequently asked questions
What causes abnormal PTH levels?
How often should I get this test?
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