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Parathyroid Hormone (Active, Serum)

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

This test measures the active form of parathyroid hormone (PTH) in your blood. PTH is a hormone produced by your parathyroid glands that helps regulate calcium and phosphate levels in your body.

Quick summary

["Active PTH helps your body maintain healthy calcium levels, which is crucial for bone health and nerve function."]

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

Key facts at a glance

LOINC
100627-9
Short code
PT Hosp Prog note
Synonyms
PT Hosp Prog note
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
physical-therapy
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 Might Be Ordered

Your doctor may recommend this test if you have symptoms like bone pain, frequent fractures, muscle weakness, or abnormal calcium levels. It could also be used to monitor conditions like hypoparathyroidism, hyperparathyroidism, or kidney disease.

What to Expect Before the Test

No special preparation is needed for this blood test. You may have a small needle inserted into your arm to draw blood, and you can resume normal activities afterward.

What the Results Mean

Results help doctors diagnose or manage conditions affecting calcium metabolism. High levels may indicate hyperparathyroidism, while low levels may suggest hypoparathyroidism or other issues.

Common Conditions Monitored

This test is often used to evaluate or monitor conditions like chronic kidney disease, vitamin D deficiency, or metabolic bone diseases.

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

PTH (Active)

Frequently asked questions

What causes abnormal PTH levels?
Abnormal PTH levels can result from conditions like hyperparathyroidism (too much PTH), hypoparathyroidism (too little PTH), kidney disease, or certain tumors. Lifestyle factors, medications, or vitamin deficiencies may also play a role.
How often should I get this test?
Frequency depends on your health condition and doctor’s recommendations. Some patients may need it yearly or more often if managing chronic diseases like kidney problems or bone disorders.
Can diet affect PTH test results?
Dietary calcium, vitamin D, and phosphate intake can influence calcium levels indirectly, but they do not typically affect PTH measurement directly. Follow your doctor’s advice on dietary adjustments if recommended for your condition.
  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