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 a toxin 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
  • Aqueous humor or intact eyeball
  • Skin (site of exposure)
  • Heart blood (collected into heparinized tube/green top Vacutainer)
  • Stomach/rumen content/intestinal content/feces (collect these last, to avoid contamination of other tissues)

Each tissue type should be placed in a separate, clean, labeled container.

In most cases, toxicology samples should be stored frozen until tested.

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

  • 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 LabNotes of interest for toxicology testing:

AHL LabNote 19 – Liver biopsy procedure in cattle

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

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 (laboratory) or ext. 54993 (Dr. F. Reggeti, Toxicologist), or email

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.