Frequently Asked Questions

When could that dead mouse you just found be the most valuable mouse in your colony?

You just heard that one of your mice from a recent surgery (or other experimental procedure) has been found dead. You know the literature, or maybe your past experience, has indicated that a 20% mortality has been seen with this procedure. But do you know why this mouse or even any of the other 20% really died?

There are a number of possibilities and knowing what the reason is can help you prevent another such loss. Errors in a surgical procedure can be corrected if you know what was done and the only way you can really know is to look. Unexpected consequences such as migration or contamination of implants, gastrointestinal problems with an ingredient in a purified diet, or species specific reactions may be avoided by modifications or changes in procedures. Some bacteria that are found in the reproductive and GI tracts of otherwise healthy research rodents can, with stress, lead to widespread infection. Knowledge of their presence in your colony and pre-treatment can prevent such losses. Even knowing that your mice have retinal degeneration may help you ensure that such animals are given more easily accessible food and water. Animal deaths only occur for a reason and knowing that reason will let you modify or change your procedures to prevent further deaths.

The Comparative Pathology Lab at the RARC has years of experience in such investigations and is here to work with you to determine what steps can be taken to reduce or prevent that “20% loss.”

P.S. The more recently the animal died the better your results may be. Severely morbid animals can also be submitted.

What is a necropsy?

A necropsy is an autopsy for animals in which all of the animal and its tissues are first evaluated by the pathologist for signs of disease. Tissues are collected for microscopic examination (histopathology). Microbiological samples are collected for culture if the gross examination suggests microbial infection. Other samples may be collected for ancillary testing (such as parasitology, molecular biology, etc.) if the gross findings suggest these are needed. Blood can be collected if the animal is presented alive. A gross report with preliminary findings is issued to the investigator and submitting veterinarian. Subsequently, histologic sections of all major organs and any grossly noted lesions are examined microscopically; the goal being to evaluate histologic changes to explain the disease process in the animal. A final report which integrates the gross and histopathologic findings with ancillary tests, is issued to the investigator and clinical veterinarian at the conclusion of the case.

When should I expect results back from a necropsy?

A gross report is typically issued within two working days of the necropsy. Histopathology reports take longer (2 - 3 weeks). Preparation and special stains of histologic slides and other tests are time – consuming, so your patience is appreciated. The pathologists will need to spend more time working on the microscopic examination of the animal than they do on the gross exam. The pathologists can, however communicate with you regarding the status of your case, what tests are pending, and what preliminary results are available if you call.

How do I submit an animal for necropsy or samples for histology?

You will need to complete the correct form (Submission Forms) for the species of animal you are submitting (or a biopsy/histology form for samples). You will also need your billing information to complete these forms.

Does it matter if the animal I want to submit is alive or dead?

The laboratory accepts both live and dead animal submissions but prefers that rodents, amphibians and small laboratory animals be submitted alive if possible. (When we are able to euthanize these animals humanely, just prior to the necropsy, the histology tissues will show less post mortem change.) We are, unfortunately, not able to accept larger animals or primates alive. These animals must be euthanized prior to submission. We ask that you submit euthanized and dead animal submissions as soon after euthanasia or death as possible and keep both dead and euthanized animals in the refrigerator (not freezer) just before you submit them.

Can necropsies be requested as a part of a research study?

Yes. Necropsies on animals can be requested both for diagnostic purposes (to explain why an animal is sick or has died) and for research purposes (to evaluate the effect of an experimental treatment, procedure, compound exposure, genetic manipulation, or other parameter on the organs of the body). Since research necropsies are generally planned to occur at particular times in a study, may involve multiple animals, and may require specialized tissue-handling procedures, we ask that you call and schedule your research necropsies well in advance and in close collaboration with the consulting pathologist. Communication with the pathologist before the beginning of the study will ensure that your research necropsies will go smoothly, the correct fixatives will be used and that all useful tissues will be collected.

What is a "phenotyping" necropsy?

A phenotyping necropsy is a research necropsy in which the goal is to define the phenotype by thoroughly examining all tissues from an animal to look for abnormalities or subtle changes attributable to a research manipulation, often a genetic change. Both experimental and control animals are examined in phenotyping necropsies. In order to uncover subtle changes due to an experimental manipulation, it is essential to compare experimental animals to controls. Phenotyping necropsies include examination of all the typical tissues evaluated during a routine necropsy but with more extensive sampling. They may also include routine assessment of tissues (such as long bones, peripheral nerves, and spinal cord) that are less commonly evaluated histologically in a diagnostic necropsy if the clinical signs, gross exam, or histology suggests a problem that might arise from these tissues.

What information should I expect to find in a necropsy report?

The gross and histopathological reports will include written descriptions of what the pathologist saw during each of the examinations and a list of any and all abnormal findings ranked based on the relative importance of each abnormality to the animal and its clinical signs. The final report of the histopathologic findings will also include the results of any serologic, microbiological, molecular, or other testing done, and will integrate all the gross, histopathological, and ancillary findings to explain, to the extent possible, the disease process in the animal. Interpretive comments may also be included. We are especially cognizant of how our findings may affect other animals in a colony or on a study, and we work closely with the clinical veterinary staff to ensure a rapid response to infectious disease problems when they are identified.

Can I request a "rush" on my necropsy?

Yes, in certain circumstances, such as when multiple animals of a group have died and others are ill. Your veterinarian is often the one to request this, as s/he is specially trained in identifying colony health issues. We will strive to expedite the results to you.

Who does the necropsies?

One of our three Board-certified veterinary pathologists will perform and/or supervise any diagnostic or research necropsy. We also participate in training veterinary pathology residents from the School of Veterinary Medicine, and in some instances, the resident may perform a necropsy under the supervision of the pathologist. In these cases, you will see two names on the bottom of your report. One will always be a Board-certified veterinary pathologist (Diplomate, American College of Veterinary Pathologists). Our veterinary technician performs necropsies on sentinel rodents. She is trained to recognize gross abnormalities, which will trigger examination by one of the veterinary pathologists.

Will you perform necropsies for me on my experimental animals that I have injected or treated?

Yes we routinely work with experimental animals. We would enjoy working with your laboratory on experimental studies. We can do this on a per-cost basis or as part of a research collaboration. Please contact one of the pathologists to discuss this. (Staff)

What does a necropsy cost?

Please call us at 608-263-6464 to discuss because it will vary with species and the extent of evaluation procedures. Note that the cost of research necropsies is higher than that for diagnostic necropsies. Research necropsies are more involved than diagnostic necropsies and require more time from both the Board-certified pathologist and the technical staff. Please discuss this with a pathologist.

My mice are injected with human cells or a human pathogen. Can you perform necropsies on BSL2 animals?

Yes. We routinely perform BSL2 necropsies in our facility at the RARC. It is essential however when you submit a BSL2 animal that you inform us of the experimental procedure and agent(s) involved and any safety concerns with the compoundsd. While these animals will be dissected under a hood with special protective gear, different equipment and/or cleaning procedures may be needed for different agents. Note: Our submission form includes questions regarding biosafety level and experimental procedures/agent exposures. We require that these sections of the form be filled out before we perform any necropsies. We can also come to a BSL2+/BSL3 facility and perform a necropsy, or you can collect tissues and submit them to us for histopathology following inactivation of any agents (for example by adequate fixation). Please submit any BSL2 animals in appropriate biosecurity packaging. Note: We may also be able to train you on how to collect tissues.

Our laboratory works with wild-caught lesser pangolins (or other unusual laboratory species). Do you do necropsies on these animals?

Yes, while we regularly do necropsies on common laboratory species, we also do frogs, fish, and birds, and other exotics as well as wild-caught species such as starlings, ground squirrels, chickadees, turtles, etc. In some instances of small colonies of wild-caught species, we can work with your laboratory to reduce your necropsy costs and enhance the health status of your colony by using a number of your diagnostic submissions as sentinel animals. The purpose of this is for your laboratory and clinical veterinarians to learn about the pathogen status of these wild-caught animals, as well as the efficacy of any treatment that may be given after capture. Dr. Gendron has 30+ years of zoo animal pathology experience involving a wide variety of exotic species. Dr. Schwahn also has 4+ years of zoo animal pathology experience.

How do I bring my tissues over to be cut so I can get slides to read?

Tissue samples should be submitted in individual containers clearly labeled with ID numbers. A histology submission form should be filled out clearly stating tissue, type of fixation (formalin/alcohol), number of slides to be cut, and the stains needed. If a specific orientation of the tissues in the block is needed, please discuss this with the histotechnologist, Beth Gray at 608-262-0933,