Companion animal histopathology tests at the AHL

AHL histopathology tests and associated fees for companion animal biopsies and in-clinic postmortems are categorized based on the number and size of samples. Please be sure to read the details for each subset of test so that you select the correct test for each case.

Also please note that for surgical margin evaluation of biopsies >2 cm diameter, the ‘tumor margin evaluation’ test must be selected in addition to the appropriate histopathology test, and an additional fee will apply for the evaluation on these large tumors. 

Test name

Test code


Histopathology, 1-2 biopsies or tissues


For submissions with 1-2 biopsies or tissues, OR multiple (6 or fewer) punch, Tru-Cut, or endoscopic biopsies

Histopathology, 3-6 biopsies or tissues


For submissions with 3-6 biopsies or tissues, OR 6-10 cm diameter

Histopathology, 7 or more biopsies or tissues


For submissions with 7 or more biopsies or tissues, OR >10 cm diameter (e.g., large tumors, spleen, brain, mammary chain, heart)

Tumor margin evaluation


Applies in addition to regular histopathology charge. For tumor excisional biopsies >2 cm diameter. Includes preparation of 4 radial margin sections. Must be requested at time of sample submission.

Systematic approach in diagnostic toxicology

Felipe Reggeti


Veterinarians frequently contact the AHL inquiring about toxicology testing for suspect intoxications or malicious poisoning, but the available information is often times limited. A toxicologic investigation is commonly far from straightforward, and requesting toxicology tests without clear direction can be unrewarding, expensive, and frustrating. Presumptive exposure does not necessarily equal intoxication.

  • A systematic approach needs to be followed, beginning with a detailed clinical history to identify potential sources, including changes in management, recent applications of pesticides, storage of chemicals and drugs, etc.
  • The veterinarian needs to perform a thorough physical exam and collect clinicopathologic data from CBC, clinical biochemistry, and urinalysis to narrow down the list of differential diagnoses. Underlying infectious, metabolic and other conditions that may have similar presentations need to be ruled out before continuing with toxicology testing. Clinical biochemistry may provide evidence that specific systems have been targeted (e.g., hepatic and renal).
  • If the case involves deaths, a complete postmortem examination is essential, including sampling of tissues for microbiology, histopathology, and toxicology. Some samples may not be necessary but should be available if needed (keep toxicology samples frozen). A postmortem exam is probably the most important aspect of the investigation, as it may indicate that toxicology testing is unnecessary. Alternatively, it could reveal lesions that are relatively specific for some toxins, or no obvious lesions at all (e.g., organophosphates).

The Toxicology laboratory at the AHL offers a wide array of tests for chemical analysis that may be helpful to support or confirm the presumptive intoxication. A few bioassays are also available; e.g., mouse inoculation test for botulism (bacteriology lab). Significance of any toxicology results must be interpreted in the context of clinical presentation and other laboratory findings.

Recommended reading: Osweiler GD. Diagnostic guidelines for ruminant toxicoses. Vet Clin North Am Food Anim Pract 2011;27:247-254.

For more information on toxicology and available tests, please see the AHL User’s Guide (