How the DNR Tests for CWD

by Anna Mitterling, Wildlife Cooperative Coordinator, MUCC

DSC_0237.JPGAs a hunter in the CWD zone, I was curious to find out more behind-the-scene details about CWD testing. What is the process like? What do they do in the lab? How long does it take for them to process my deer’s results? So, I asked if I could go into the lab and help them with their testing. They agreed and I worked in the lab for a few days to better understand the process.

Aging DeerBefore I get into the testing process, here are some important reminders I have learned during my time working in the lab:

1. It is illegal to salvage road kill deer in the CWD zone. Let the DNR pick it up.

2. If you illegally bring deer into the state, CO’s will take your deer, and it will come to the lab for testing (and you will be prosecuted!). Know the transportation laws when bringing game into Michigan and don’t be “that guy” who spread CWD. We tested seven out-of-state deer in one day that CO’s had confiscated.

3. If you want to mount your deer, take it to the check station and let them know. They will give you a tag, and then you can take your deer to the lab yourself. The lab will take your deer, remove the lymph nodes, and hand your deer back to you. You can also get a special tag that lets you take your deer to the taxidermist so they can remove the cape prior to going to the lab. Just go to a check station first.

4. The lab staff genuinely care about the status of the deer they test. They are invested in their job of evaluating the health of the deer they handle.


The process of testing a deer for CWD starts with you, the hunter. After a successful kill, tag your deer, and within 72 hours bring the entire deer to a check station near you.

This is legally required if you hunt in the 9 township CWD Core Area, and it is highly recommended if you hunt in the CWD Management Zone (remainder of Clinton, Shiawassee, and Ingham Counties). If you live outside this area, you can still take your deer head to a check station near you and request that it gets test for CWD. Once checked at a DNR check station, the heads are collected and then transported later that evening or the following day to the DNR Wildlife Disease Lab at Michigan State University. Transportation to the lab will take longer for check stations outside of the CWD area, as sample sizes are small.

Checking Lymph NodesDuring firearm season, the lab receives large deliveries of deer heads in the morning, anywhere from 50 to 300 or so for CWD! In addition they also test n northeast Michigan deer for TB. If you submitted a deer for CWD testing, you will also notice they test for TB too. The TB test is rather simple. There are three sets of lymph nodes that are evaluated for inconsistencies, abscesses, or strange looking fluid around them. If the lymph nodes appear to be healthy, the deer is given a TB free evaluation.

After the lymph nodes are checked for TB, the pair by the brain stem are pulled for additional testing for CWD. Those lymph nodes are then chopped into tiny pieces and then placed into a test tube. The remainder of the nodes are stored in a bag incase further testing is needed. The test tubes are given to a MSU diagnostic lab where the ELISA (enzyme-linked immunosorbent assay) test is conducted. In the event of a possible positive CWD result, a sample of the lymph node is sent to Iowa, where the National Veterinary Services Laboratory,  “gold standard” testing lab, is located.

DSC_0339.JPGThe whole process for checking and pulling the lymph nodes takes just a matter of minutes. Results from the ELISA test are usually received by the DNR 24-48 hours after the lymph nodes are submitted for testing, and are then made available for hunters to check online. In the event that a deer comes back as a suspect for CWD, the hunter will receive a phone call from the DNR.

Working with the Wildlife Division lab team was a great experience. Even in light of the serious threat CWD poses to our state, they are positive, upbeat, and make the most of things. They are hardworking and dedicated to helping to establish a baseline for where we are with CWD here in Ingham County. While this disease has created an inconvenience for us as hunters, the staff at DNR are tirelessly working overtime to get us results on our venison.

I want to thank the Lab Team for allowing me to spend a few days with you. You’re a great group of people and the work you do is appreciated and valued. Thank you! Also, to DNR staff in general, job well done. Thank you for all you are doing!


Helpful Links:

Check Stations

Transportation Rules

Additional CWD information


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  • commented 2015-12-04 08:33:58 -0500
    Tiny further detail: The ELISA is using antibodies to detect miss-folded PRNP protein, which is what transmits and causes the disease. Internet search will give more on how most ELISAs work in general. The miss-folded PRNP protein is the thing that is so resistant to being degraded (astonishingly so).