Companion animal histopathology test codes explained

Companion animal histopathology test codes explained

Josepha DeLay

Animal Health Laboratory, University of Guelph, Guelph, ON.

AHL Newsletter 2019;23(3):17.

Histopathology tests offered by the AHL for companion and non-food animals are arranged in 3 price categories that reflect the number and/or size of the biopsies or postmortem samples. The categories translate into the number of slides required for the case, which in turn reflects the cost (for reagents and supplies, and technical and professional time) for each case.

Companion animal histopathology test codes and criteria are as follows:

  • histcm1: Histopathology, companion / other, 1-2 biopsies or tissues < 6 cm, OR multiple (6 or fewer) punch, trucut, or endoscopic biopsies.
  • histcm2: Histopathology, companion / other, 3-6 biopsies or tissues, OR biopsy 6-10 cm.
  • histcm3: Histopathology, companion / other, 7 or more biopsies or tissues, OR biopsy >10 cm.

Additional charges also apply to those samples from any species requiring the following special procedures for histologic processing:

  • Decalcification, examples: digit amputations, bone biopsies.
  • Hoof or nail softening.
  • Tumor margin evaluation (for biopsies >2 cm): Please inform us at the time of sample submission if margin evaluation is required.
  • Complex cases requiring pathologist intervention at the trimming stage, examples: limb amputations, splenectomies, large mammary resections.

Please see the online AHL Fee Schedule for pricing.

When necessary, AHL histotechnologists and pathologists will adjust requested tests and associated fees to reflect the samples that we receive. We will make an effort to inform clients whenever these changes must be made. However clients must be aware of the test criteria described above and choose the appropriate histopathology test for individual cases submitted to the AHL.

Please contact Dr. Josepha DeLay with any questions about histopathology submissions:

519-824-4120 ext 54576 or   AHL

Disseminated mycosis in a German Shepherd dog

Disseminated mycosis in a German Shepherd dog

Murray Hazlett, Lisa Ledger, Hugh Cai

Animal Health Laboratory, University of Guelph, Guelph, ON.

AHL Newsletter 2019;23(3):18-19.

A male 3-y-old German Shepherd was euthanized because of renal failure, vomiting, and uveitis. The dog had developed hind-end weakness over the previous 2 weeks. The dog was autopsied at the clinic and selected tissues (liver, kidney, spleen, small intestine) were submitted for histology. In the section of kidney, there was a large zone of infarction with mineralization and fibroplasia. Several other smaller infarcts were seen. There were scattered multinucleate giant cells present, and objects suspicious for fungal hyphae could be seen; these were verified as fungal hyphae with a silver stain of the section (Fig. 1). Morphologically they were suspected to be Aspergillus spp. Testing of formalin-fixed paraffin-embedded tissue scrolls for fungal PCR products was unfruitful, and the fungus could not be further identified.

A search of pathology cases since 2007 for fungal lesions in dogs reveals most are either associated with aspergillosis (7 cases) or blastomycosis (37 cases). Two other cases of disseminated mycosis likely associated with Aspergillus spp. were both in German Shepherds (Table 1).

Most cases of disseminated aspergillosis occur in German Shepherd dogs.1 Common clinical signs are vertebral pain, anorexia and wasting. CNS involvement, lymphadenopathy, and endophthalmitis are also reported manifestations.   AHL

Table 1. Mycoses in AHL canine pathology submissions.*




Age (y)




German Shepherd





German Shepherd





German Shepherd




Nasal aspergillosis

1 German Shepherd, 1 Golden Retriever, 1 Standard Poodle, 2 mixed breed



Blastomyces – all cases

Blastomyces dermatitidis

37 cases (12 disseminated or pneumonic)



*Diagnosis usually based on fungal morphology in histologic sections.

Disseminated mycosis in a German Shepherd dog.

Figure 1. Disseminated mycosis in a German Shepherd dog. A. Loss of renal parenchyma with an intense infiltrate of mixed inflammatory cells (arrow). H&E. B. Areas of granulomatous inflammation with multinucleate giant cells (arrow). (H&E). C. Suspicious fungal hyphae in H&E section (arrow) confirmed with silver stain. D. Methenamine silver stain.


1. Day MJ. Canine disseminated aspergillosis. In: Green, Infectious Diseases of the Dog and Cat, 3rd ed. 2006:620.