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Parathyroid Hormone (PTH) - Active (Intact)

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

This test measures your intact (full-length) parathyroid hormone levels, which regulate calcium and phosphate balance in your body.

Quick summary

["Active PTH helps manage bone health and calcium levels by signaling your body to release calcium from bones or retain it in the kidneys."]

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

Key facts at a glance

LOINC
16163-8
Short code
PTH-Intact 1h p chal SerPl-mCnc
Synonyms
PTH-Intact 1h p chal 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 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’s also used to monitor conditions like hyperparathyroidism or kidney disease that affect calcium metabolism.

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 on blood thinners, let your doctor know before the test.

What the Results Mean

Results help diagnose or monitor conditions linked to abnormal calcium or bone metabolism. High levels may indicate overactive parathyroid glands, while low levels could suggest vitamin D deficiency or kidney issues.

Common Conditions Affecting Results

Conditions like hyperparathyroidism (too much PTH), hypoparathyroidism (too little PTH), kidney disease, or vitamin D deficiency can alter PTH levels. Other factors, such as medications or recent calcium intake, may also influence results.

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

Active PTH (Serum)

Frequently asked questions

How often will I need this test?
Your doctor will determine how often you need this test based on your symptoms, medical history, and treatment plan. Some patients may need it monthly, while others may only need it once or twice a year.
What are the normal ranges for this test?
There are no standard numeric reference ranges provided here because they can vary by lab and patient factors. Your results will be compared to your specific lab’s reference values, and your doctor will interpret them in context with your health.
Can I eat or drink before this test?
You can eat and drink normally before this test unless your doctor advises otherwise. Avoiding certain foods or fluids may not be necessary for this blood test.
  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