Sample collection for suspected toxicology cases

Toxicology

The AHL Toxicology section serves Ontario by safeguarding public and animal health via identification of compounds that can negatively affect animals and humans, along with analysis of animal feeds and animal-based foods for contaminated with synthetic chemical residues and toxins.  In keeping with the mission statement of the AHL, the Toxicology section strives to provide accurate results within acceptable turnaround times.

The broad range of target compounds provided by the Toxicology section can be determined on a variety of matrices and includes both natural toxins and synthetic toxicants, such as mycotoxins, environmental toxins, pesticides, rodenticides, drugs, and heavy metals. The laboratory can also perform analysis for nutritionally relevant compounds such as vitamins and trace metals.

Our laboratory also provides case consultation and may assist in field investigations of possible animal toxicosis.  We have active test development for emerging toxicants using state-of-the-art methodology.

The goals of any toxicology investigation should be to:

• Identify the source(s) of the toxicant and confirm exposure.
• Identify factors contributing to morbidity/mortality.
• Assess the level of contamination.
• Assess possible interventions.
• Assess any risk to the food chain.

Some questions to consider:

• Are feed and chemical storage containers on the premises labelled properly?
• Are feeds stored adjacent to chemicals?
• Is feed stored appropriately to prevent spoilage?
• Is there any visible mold on or in feedstuffs, or do feedstuffs smell moldy?
• What are the potential risks in the environment, facility or home? Are there any recent obvious changes in the environment or management?
• Do the animals have access to trash, building materials, medicines, including those intended for other species, toxic plants, or substances provided by non-caretakers?

Submitting cases for postmortem examination

• Always enclose a detailed history, including clinical signs and lesions.
• Include tentative diagnoses, list of drugs administered, and the response to treatments.
• A complete history may enable us to decide which additional tests are warranted.

Sample collection for suspected toxicology cases

It is good practice to follow the guidelines presented here for collecting samples suitable for toxicologic analysis, even if exposure to a toxic substance is not suspected at the time of the postmortem.  In situations involving an animal death, a thorough postmortem and histopathology should be performed before toxicologic analysis is ordered.

For general instructions for collecting samples from a field postmortem, refer to:

AHL LabNote 2 – Tips for practitioners for field postmortems

AHL LabNote 42 – Field and clinic postmortems: Simplified protocol and image list

Always wear appropriate protective equipment when performing postmortem exams or collecting potentially hazardous samples. Wearing gloves may also be important for protecting sample integrity.

For potential toxicologic investigation, collect the following:

• Brain
• Liver, without gall bladder
• Kidney
• Fat
• Urine
• Intact eyeball (preferred) or aqueous humor
• Skin (site of exposure)
• Heart blood (collected into heparinized tube/green top Vacutainer)
• Stomach/rumen/intestinal content/feces (collect these last, to avoid contamination of other tissues)

Each tissue type should be individually placed in a separate, clean, labeled container.
In most cases, toxicology samples should be stored frozen until tested.

If a particular toxin/toxicant is suspected of being involved in animal morbidity or mortality, you may want to collect other samples, depending on possible routes of exposure:

• Suspect materials
• Environmental samples (paint, soil, etc.)
• Feed samples
• Water samples
• Heparinized whole blood (20 mL or more, green-topped Vacutainer) from live animals
• Urine from live animals

Links to other AHL publications of interest for toxicology testing:

AHL LabNote 19 – Liver biopsy procedure in cattle

AHL LabNote 59 – GC/MS-LC/MS multi-residue method  

AHL Newsletter 2021;25(1):22.  Making sense of the toxin screen

Consult with the laboratory or toxicologist about any special sampling requirements. It is especially important to contact the laboratory in advance of sending any samples for a case that may be involved in litigation or forensic investigation, requiring chain-of-custody handling.

The Toxicology section of the Animal Health Laboratory can be reached at:

519-824-4120 Ext. 57215 or jcharter@uoguelph.ca – Jeffrey Charters, Technical Supervisor

519-824-4120 Ext. 54993 or freggeti@uoguelph.ca - Dr. F. Reggeti, Toxicologist

For more information about test offerings, specimen requirements, or submittal procedures, contact AHL Specimen Reception at 519-824-4120 Ext. 54530 or visit the AHL website.