Parathyroid Hormone (PTH) Test

A parathyroid hormone (PTH) test measures the amount of PTH in your blood. PTH helps control calcium levels. It is ordered when calcium is abnormal or to check parathyroid function.

What it measures

Parathyroid hormone (PTH) — The main hormone that regulates calcium in your blood.
Calcium — Often tested alongside PTH to see how the two relate.
Phosphate — Another mineral that PTH helps balance.
Vitamin D — Works with PTH to manage calcium absorption.

Who it is for

Doctors order this test when a routine calcium test is high or low, or when they suspect a parathyroid problem.

Preparation

No fasting is usually required. Tell your doctor about all medications and supplements, as some can affect PTH levels.

Results and what they mean

Results are reported as a number with a reference range. Your clinician interprets them along with calcium and other tests. This is general information, not medical advice.

How to order this test

Choose the test and place a confidential order online.
Select a certified collection site and pick a time that suits you.
Have your specimen collected — most draws take only a few minutes.
Review results in a secure portal, typically within 1–3 days.

Preparation, hours, and pricing vary by site; confirm details directly with the lab before your visit.

Availability by state

Direct-access online ordering for the parathyroid hormone (pth) test is available in most states. It is currently unavailable in 6 states:

Everywhere else you can order confidentially and collect your sample at a certified site. Browse by state →

Frequently asked questions

Do I need to fast for a PTH test?

Usually no. But follow any instructions from your doctor.

What can affect my PTH level?

Calcium and vitamin D levels, kidney function, and some medicines can affect PTH.