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Parathyroid Hormone (Active), Intact

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

This test measures the active, intact form of parathyroid hormone (PTH), a key hormone that helps regulate calcium levels in your body.

Quick summary

["Active PTH helps maintain healthy calcium balance and bone health."]

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

Key facts at a glance

LOINC
47717-4
Short code
PTH-Intact 2h p Ca SerPl-mCnc
Synonyms
PTH-Intact 2h p Ca SerPl-mCnc
Category
electrolyte
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 an active PTH test to check for conditions that affect calcium metabolism, such as hypoparathyroidism (low PTH), hyperparathyroidism (high PTH), or kidney disease. It can also help diagnose or monitor conditions like pseudohypoparathyroidism or vitamin D deficiency.

What to Expect Before the Test

No special preparation is needed. You may have a small needle inserted into a vein in your arm or hand to draw blood. If you’re fasting, follow your doctor’s instructions. Avoid certain medications that could affect results for 24 hours before testing.

What the Results Mean

Results are interpreted by your healthcare provider based on your symptoms, medical history, and other lab tests. Abnormal levels may indicate imbalances in calcium or PTH, which can lead to bone problems, muscle weakness, or other health issues.

Common Conditions Linked to PTH Levels

High PTH levels might suggest overactive parathyroid glands, kidney disease, or vitamin D deficiency. Low PTH levels could indicate underactive thyroid, kidney issues, or rare genetic disorders affecting calcium regulation.

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.

Clinical Significance

Short name

Active PTH (Intact)

Frequently asked questions

What causes false high or low results?
False high results may occur if you’re dehydrated, taking certain medications (like calcium supplements or antacids), or have recent kidney problems. False low results could happen if you’re taking medications that lower PTH or have recent blood transfusions. Always discuss your medications and health history with your doctor before the test.
How often should I get this test?
Your doctor will determine how often you need this test based on your condition, symptoms, or treatment plan. Regular monitoring may be needed if you have chronic kidney disease, bone disorders, or are on long-term calcium or vitamin D therapy.
Can diet or supplements affect this test?
Yes, high calcium intake (from dairy, supplements, or certain foods) or vitamin D supplements can temporarily raise PTH levels. Avoid large doses of calcium or vitamin D for 24 hours before testing unless instructed otherwise.
  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