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Parathyroid Hormone (Active), Intact

Published: August 9, 2026Updated: August 16, 2026

This test measures the active form of parathyroid hormone (PTH) in your blood, which helps regulate calcium levels in your body.

Quick summary

["Active PTH supports bone health and calcium balance; abnormal levels may indicate conditions like hypoparathyroidism or hyperparathyroidism."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
50525-5
Short code
PTH-Intact sp1 SerPl-mCnc
Synonyms
PTH-Intact sp1 SerPl-mCnc
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 Is This Test Done?

Your doctor may order this test to check for problems with your parathyroid glands, which produce PTH. It’s often used when you have symptoms like muscle weakness, bone pain, or abnormal calcium levels, or if you have conditions like kidney disease or osteoporosis.

What Does the Test Measure?

Intact PTH measures the full-length, biologically active form of PTH in your blood. This is important because some tests only measure fragments of PTH, which can give misleading results.

How Is the Test Performed?

A blood sample is taken from a vein in your arm. The sample is sent to a lab where it’s analyzed using an immunoassay method to detect the intact PTH protein.

What Are Common Results?

Results are compared to a reference range provided by your healthcare provider. Low levels may suggest hypoparathyroidism, while high levels could indicate hyperparathyroidism or other metabolic issues.

Reference range

INR: 0.8-1.2 (warfarin: 2.0-3.0)N/A

Specimen: serum

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

Intact PTH

Frequently asked questions

What causes abnormal PTH levels?
Abnormal PTH levels can result from thyroid disorders, kidney disease, vitamin D deficiency, or genetic conditions. It may also be affected by medications like calcium supplements or certain anticonvulsants.
How long does it take to get results?
Results are typically available within 1–3 business days, depending on lab processing times. Your doctor will discuss the findings with you during your follow-up visit.
Can lifestyle changes affect PTH levels?
Yes, diet (especially calcium, vitamin D, and phosphorus intake) and physical activity can influence PTH. However, your doctor will guide you on how lifestyle changes may interact with your test results.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

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.

Medical Disclaimer

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