Effective July 18, 2022, the MSU VDL Toxicology Section will perform analysis for anticoagulant rodenticide (AR) panels (test codes 70066 and 70015) using a different instrument and test method.

Test results will no longer include a numeric concentration for each rodenticide compound. If a compound is detected, “Positive” will be reported next to the compound of concern. For negative results, a “<” value will be reported to clarify the reporting limit and sensitivity of the instrument (UPLC-MS/MS).

Moving to a different instrument and not quantifying compounds will improve turnaround time for this assay and clients will get results faster. Additionally, reports will be more straightforward and easier for clients to interpret.

In the simplest of terms, the purpose of the AR test conducted in blood samples is to identify compounds associated with a coagulopathy that is responsive to vitamin K treatment to determine an appropriate duration of treatment.

For the post-mortem patient, the purpose of testing for ARs in liver is to help distinguish between a rodenticide-induced coagulopathy and coagulopathy brought about by disseminated intravascular coagulation, congenital factor deficiencies, liver disease, chronic gastrointestinal malabsorption, or exposure to sulfaquinoxaline.

In both scenarios, the primary goal of testing is to establish the identity of the AR involved in what may be an otherwise unexplained coagulopathy.

Since its inception, the Toxicology Section provided clients with a numeric concentration for each detectable rodenticide compound contained within the diagnostic test list performed in the AR panels. This numeric value has been of interest predominantly for researchers but has been a longstanding source of confusion for veterinary clinicians seeking to either treat an animal with known exposure to AR’s or attempting to render causation to an animal’s death.

Because exposures to ARs take several days to negatively affect clotting factors and incite a coagulopathy for the patient, the numeric value reported does not provide any clarity as to the amount of rodenticide initially ingested or the temporal relationship between its consumption and the animal’s clinical presentation.

Numeric quantitation will be provided for researchers through a referral laboratory if requested.

The Nutrition and Toxicology Section has also modified the existing convulsant panel (test code 70021 which includes bromethalin, Penitrem A, Roquefortine, and strychnine) to better serve our clients.

Effective July 18th, 2022, the MSU VDL's convulsant panel will measure desmethylbromethalin, bromethalin’s bioactive metabolite. A standalone test will be available for analyzing bromethalin in source materials suspected of contamination or product misuse.

Polychlorinated Biphenyls (PCBs, test code 70045) and Chlorinated pesticides (test code 70020) are temporarily unavailable while upgrades are made to the current methodologies. We anticipate bringing back both of those tests in January 2023 but that is subject to change. We apologize for any inconvenience this causes to our clients and look forward to resuming this testing as soon as possible.