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Parathyroid Hormone, Serum

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

This test measures the level of parathyroid hormone (PTH) in your blood. PTH helps regulate calcium and phosphate levels in your body.

Quick summary

["PTH levels can indicate whether your bones, muscles, or nerves may be affected by low calcium."]

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

Key facts at a glance

LOINC
94637-6
Short code
M avium paraTB Ab Titr Ser CF
Synonyms
M avium paraTB Ab Titr Ser CF
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
comp-fix
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 if you have symptoms like muscle weakness, bone pain, or frequent bone fractures. It could also be done to check for conditions like hypoparathyroidism (low PTH) or hyperparathyroidism (high PTH), or to monitor treatment for these conditions.

What Does a High or Low Level Mean?

High PTH levels might suggest hyperparathyroidism, which can lead to problems like kidney stones, weak bones, or heart issues. Low PTH levels could indicate hypoparathyroidism, causing muscle cramps, numbness, or irregular heart rhythms.

How Is This Test Done?

A blood sample is taken from a vein, usually in your arm. You may feel a small pinch when the needle goes in, but it usually doesn’t cause much discomfort afterward.

What Should I Expect Before or After the Test?

No special preparation is needed. You can eat and drink normally. After the test, you may feel a slight bruise or soreness at the injection site, but this usually goes away quickly.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance: PTH plays a critical role in calcium metabolism. Elevated levels may indicate overactive parathyroid glands, while low levels can point to deficiencies or other endocrine disorders. Regular monitoring is important for patients with chronic kidney disease or those on certain medications.

Short name

PTH (Serum)

Frequently asked questions

What causes abnormal PTH levels?
Abnormal PTH levels can result from conditions like kidney disease, vitamin D deficiency, or tumors affecting the parathyroid glands. Certain medications and genetic disorders can also influence PTH levels.
How long does it take to get the results?
Results are typically available within 1 to 3 business days, depending on your lab’s processing time.
Can I eat or drink before this test?
Yes, you can eat and drink normally before this test. No special preparation is required.
  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