Skip to content

Serum or Plasma Parathyroid Hormone (PTH) Concentration

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 helps control calcium balance and may indicate potential issues with your thyroid or bones."]

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

Key facts at a glance

LOINC
70671-3
Short code
M avium paraTB Ab Mlk Ql IA
Synonyms
M avium paraTB Ab Mlk Ql IA
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
ia
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 (PTH)?

PTH is a hormone produced by your parathyroid glands, which are small glands located near your thyroid. These glands release PTH to help your body maintain healthy levels of calcium and phosphate in your blood. When your calcium levels drop, PTH signals your body to release calcium from bones and absorb it from your intestines. Too much or too little PTH can affect your bones, kidneys, and heart.

Why Might You Need This Test?

Doctors may order a PTH test if you have symptoms like bone pain, frequent fractures, kidney stones, or unexplained high calcium levels. It’s also used to diagnose conditions such as hyperparathyroidism (too much PTH) or hypoparathyroidism (too little PTH).

How Is the Test Performed?

A blood sample is taken from a vein in your arm. The sample is sent to a lab for analysis. The test measures the amount of PTH in your serum or plasma.

What Are Common Results?

Results are reported in picograms per milliliter (pg/mL) or picomoles per liter (pmol/L), but exact ranges can vary by lab. High or low levels may signal underlying health concerns.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

PTH

Frequently asked questions

How does PTH affect my health?
High PTH levels may indicate hyperparathyroidism, which can lead to weak bones, kidney problems, or heart issues. Low PTH levels may suggest hypoparathyroidism, causing muscle cramps, numbness, or irregular heartbeats. Your doctor will discuss results in the context of your symptoms and medical history.
What causes abnormal PTH levels?
Abnormal PTH levels can result from conditions like kidney disease, vitamin D deficiency, thyroid disorders, or tumors affecting the parathyroid glands. Lifestyle factors, such as diet (low calcium or vitamin D) or certain medications, may also influence results.
Can I prepare for this test?
No special preparation is needed, but avoid eating or drinking anything (except water) for 8–12 hours before the test if instructed by your doctor.
  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