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Parathyroid Hormone (Active), Intact

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

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

Quick summary

["Your blood calcium and bone health depend on PTH levels—this test helps doctors check if they’re too high or too low."]

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

Key facts at a glance

LOINC
70664-8
Short code
PTH-Intact IO % Dif SerPl
Synonyms
PTH-Intact IO % Dif SerPl
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 Matters

PTH controls calcium by signaling bones to release it or kidneys to retain it. Low levels can weaken bones, while high levels may cause kidney stones or heart issues. This test helps diagnose conditions like hypoparathyroidism or hyperparathyroidism.

What to Expect

A blood sample is drawn from your arm, usually in a doctor’s office or lab. Results take 1–3 days. No special prep is needed, but fasting isn’t required.

Common Conditions Checked

Doctors order this test if you have symptoms like muscle weakness, frequent bone fractures, or unexplained calcium imbalances. It’s also used to monitor treatments for conditions like kidney disease or vitamin D deficiency.

How Results Are Used

Results guide treatment plans for bone disorders, kidney function, or hormonal imbalances. Your doctor will compare your levels to your symptoms and other test 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.

Parathyroid hormone (PTH) is essential for maintaining calcium and phosphorus balance. Abnormal levels can lead to serious health issues, including bone disease, kidney stones, or heart problems. This test helps identify whether your levels are within the normal range or need adjustment.

Short name

Intact PTH

Frequently asked questions

What does an abnormal PTH result mean?
Abnormal results may signal conditions like hypoparathyroidism (low PTH), hyperparathyroidism (high PTH), or kidney disease. Your doctor will review your symptoms and other tests to determine the cause.
Do I need to fast before this test?
No fasting is required for this blood test. However, always follow your doctor’s instructions for any specific preparations.
How long will I need to wait for results?
Results typically arrive within 1–3 business days. Your doctor will discuss them with you during your follow-up visit.
  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