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: Parathyroid Hormone, Serum or Plasma [Mass Concentration]

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

: This test measures the amount of parathyroid hormone (PTH) in serum or plasma, a key regulator of calcium and phosphorus balance in the body.

Quick summary

[": PTH testing helps evaluate parathyroid gland function and calcium metabolism."]

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

Key facts at a glance

LOINC
104940-2
Short code
CT Hip ArMass for BMD
Synonyms
CT Hip ArMass for BMD
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
ct
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

: What Is Parathyroid Hormone?

: Parathyroid hormone is produced by the parathyroid glands, small glands near the thyroid in the neck. PTH helps regulate blood calcium levels by acting on bones, kidneys, and the intestines.

: Why the Test Is Ordered

: Your healthcare provider may order this test when you have abnormal calcium levels or symptoms that suggest a parathyroid problem. It is often checked alongside calcium and sometimes phosphorus and vitamin D.

: How the Sample Is Collected

: A small blood sample is drawn from a vein in your arm. Depending on your provider's instructions, you may need to fast before the test, so follow any preparation directions you are given.

: Understanding Your Results

: Results are interpreted together with your calcium and other related test results. A value that falls outside the laboratory's reference interval may or may not indicate a problem, and only your provider can determine what your results mean for you.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

: PTH testing is significant because abnormal levels can indicate conditions such as hyperparathyroidism or hypoparathyroidism and help explain disturbances in calcium regulation. Interpretation should always be done in the context of calcium, phosphorus, vitamin D, kidney function, and the clinical picture.

Short name

: Parathyroid Hormone (PTH)

Frequently asked questions

: Do I need to fast for a PTH test?
: Fasting requirements vary. Follow the specific instructions from your provider or the laboratory, which may differ depending on what other tests are being drawn at the same time.
: Can PTH be checked alongside other tests?
: Yes. PTH is commonly ordered with calcium and may also be interpreted with phosphorus, vitamin D, and kidney function tests to give a fuller picture of calcium metabolism.
: What does an abnormal PTH result mean?
: An abnormal result may suggest the parathyroid glands are producing too much or too little hormone, but it must be interpreted with your calcium level and other findings. Discuss your results with your healthcare provider.
  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