Does Freezing PPID Test Samples Impact the Results?

Results from a study on a small population of horses suggest that freezing samples for short periods before testing won’t impact the results.
Please login

No account yet? Register


Freezing PPID test samples
Vets have a few PPID testing options, the most common of which is measuring horses' blood ACTH levels, which tend to be elevated in affected horses. | Photo: Alexandra Beckstett/The Horse

It wasn’t long ago that veterinarians diagnosed pituitary pars intermedia dysfunction (PPID, previously known as equine Cushing’s disease) based solely on clinical signs. But as their understanding of the disease progressed, so did the diagnostic protocols and tests.

Today, vets have a few PPID testing options, the most common of which is measuring horses’ levels of adrenocorticotropin hormone (ACTH), which tend to be elevated in affected horses.

This hormone, however, is fragile in whole blood samples, meaning its levels can fluctuate if not handled carefully, said John Haffner, DVM, an associate professor at Middle Tennessee State University, in Murfreesboro

Create a free account with to view this content. is home to thousands of free articles about horse health care. In order to access some of our exclusive free content, you must be signed into

Start your free account today!

Already have an account?
and continue reading.


Written by:

Erica Larson, former news editor for The Horse, holds a degree in journalism with an external specialty in equine science from Michigan State University in East Lansing. A Massachusetts native, she grew up in the saddle and has dabbled in a variety of disciplines including foxhunting, saddle seat, and mounted games. Currently, Erica competes in eventing with her OTTB, Dorado.

Related Articles

Stay on top of the most recent Horse Health news with

FREE weekly newsletters from

Sponsored Content

Weekly Poll

sponsored by:

What signs does your horse show when he has gastric ulcers? Please check all that apply.
33 votes · 79 answers

Readers’ Most Popular

Sign In

Don’t have an account? Register for a FREE account here.

Need to update your account?

You need to be logged in to fill out this form

Create a free account with!