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CWD Sample Submission for IHC Testing


Ohio has robust Chronic Wasting Disease (CWD) surveillance programs in both captive and free-ranging deer. In 2020, the Ohio Department of Natural Resources (ODNR) Division of Wildlife identified Ohio's first positive test for CWD in a wild Ohio white-tailed deer in Wyandot County. A second positive test was identified in March 2021 during a controlled hunt on the Killdeer Plains Wildlife Area refuge, within 2 miles of the first positive location.

The United States Department of Agriculture (USDA) made changes in 2018 to the required procedures for sample collection for CWD testing (refer to the USDA’s sample collection guidance card). Please see the information below for detailed submission requirements for veterinarians. Note that both fresh and formalin-fixed samples are now required.

*NEW June 2021*

Watch our YouTube video for proper collection techniques for CWD sampling

General ADDL Laboratory Submission and Shipping Guidelines

As of January 1, 2021, the official ID must be submitted with the fresh ear tissue to which it was attached at the time of the animal’s death, per the Ohio Administrative Code.  If no official ID is present, the collector must affix one and record the information. Microchips must be submitted with the tissue and hide in which they are embedded.

Call the ADDL with any questions or concerns at 614-728-6220.

Article revised in December 2020 by Lauren Cain, RVT, ADDL Pathology Section

Article written in December 2018 by Dr. Jeff Hayes, DVM, MS, ADDL Pathology Section Head

Formalin-fixed tissue

(10:1 ratio of formalin to tissue sample)


After removing the brainstem from the foramen magnum, ensure the proper obex sample (bifurcation or “V”) is preserved. Further trim the brainstem section by making a transverse cut ¾ inch in front of the “V” shape bifurcation and an equal distance behind the bifurcation. Place the trimmed obex into the formalin jar.

Medial Retropharyngeal Lymph Nodes (MRPLNs)

Remove each left and right MRPLN as done previously, now, longitudinally incise each lymph node. Place half of the left and half of the right node into the formalin jar, and the other halves into a whirl-pak bag (see below).

Fresh tissue

(collect samples in one labeled whirl-pak bag)


Place the rostral and distal pieces of brainstem in the labeled bag.

Retropharyngeal Lymph Nodes

Place the other halves of each node into the same bag.

ID Tags And Skin

Effective January 1, 2021, the owner of the captive whitetail deer must submit the animal's official identification device and a piece of fresh ear tissue that was directly attached to the animal's official identification device at the time of the animal's death. Please place it in the labeled bag and submit with other fresh tissues. DO NOT PLACE IN FORMALIN.