Uses

• To determine the cause of death in a single animal (when either the owner or veterinarian wishes to understand the cause of death).
• To determine the cause of death in a multiple animal case (when such information may help prevent further deaths, or aid in determining appropriate therapy, in remaining animals within the group at risk).
• To confirm or refute the clinical diagnosis (clinical audit and quality control/morbidity and mortality investigations).
• To check whether other lesions were overlooked (clinical audit and quality control).
• To refine the diagnosis or more clearly define the extent of the lesion(s).
• To confirm or refute the validity of interpretations made using ancillary aids such as radiography, ultrasonography, clinical chemistry, MRI, etc (providing feedback to allow retrospective assessment of the original data in the light of the morphological findings post-mortem).
• For research (in experimental or regulatory procedures).
• For education (in both undergraduate and post-graduate environments).
• For legal purposes, eg suspected poisoning or other malicious act, also to confirm or refute allegations of cruelty, to confirm or refute allegations of incompetence such as might occur after post-surgical or intra-operative deaths, to satisfy criteria for insurance claims.

Advantages

• Aiding client grieving process after unexpected deaths, usually by providing some form of closure.
• Providing information which may prevent further deaths in other animals at risk. This is a key diagnostic step used in farm animal disease investigations and should not be overlooked in companion animal outbreaks, eg amongst litters of puppies.
• Providing an important means of quality assessment and clinical audit in diagnosis.
• Providing information which should allow more accurate interpretation of ancillary diagnostic aids, including imaging techniques, ie the provision of ground-truth data which may be used to fact check or compare to data received by other means.
• Allows discovery of new diseases, or confirmation of absence of specified diseases, such as spongiform encephalopathies in the domestic environment, or evidence of toxicity in the regulatory environment.
• Provides evidence for resolution of legal issues.
• The knowledge gained helps professional satisfaction and client satisfaction.

Disadvantages

• Requires specific facilities, equipment and expertise to achieve the best outcome.
• Incurs costs (capital, professional and material).
• May spread disease if adequate precautions are not undertaken.
• Safety issues require addressing (risk of infection, risks of injury from equipment, risks of injury from lifting cadavers).

Alternative techniques

• Consider using a professional specialist service, such as state, commercial or university service.
• Consider restricting examination to only specified organ systems (so-called partial post-mortem examinations) if time and/or money are limiting factors.
• To cover costs of undertaking post-mortem examinations, consider various options including direct charging to the serviced client, by indirectly charging all clients through a cost-spreading or levy system (thus making PMEs available 'free' of direct charge), or by funding the provision of PMEs by contribution from practice/institute funds (since there are benefits to the practice, outlined above in Pros, from providing such a service).
• Histology techniques and histopathological interpretations are typically provided only by specialists, but consider undertaking the gross post-mortem examination yourself and collecting samples for examination by the specialist.
• Many commercial and university laboratories can provide advice on sample collection, and likely charges. Some services have different pricing schedules for examination of histological specimens collected at post-mortem examination elsewhere (so-called "post-mortem in a jar").

Time required

Preparation

• Little preparation time if facilities and equipment are in place.
• Protective clothing should be worn .

Procedure

• Examination of only a restricted set of organ systems, such as confirming a diagnosis or collecting a restricted set of specific tissues may be rapidly achieved in a matter of minutes, depending on the experience of the individual.
• More thorough, systematic examinations may take much longer, depending on extent of the examination, perhaps an hour or more for a systematic examination excluding the spinal cord.
• As a guideline, in professional examinations, candidates may be allowed 3 h for a post-mortem examination of 1 or 2 animals (excluding associated histology).

Decision taking

Criteria for choosing test

• Consider if any conflict of interest may be present, if legal issues are possible, eg if there is a question of professional negligence relating to the case.
• Consider the limitations of undertaking a cosmetic examination.
• Obtain specialist advice, where appropriate, prior to the examination (advice on fixation, samples to collect, media for microbiological samples).
• Cadavers which have been frozen will have marked ice crystal distortion of histological architecture, which will severely limit the utility of histopathological examinations. However, be aware that useful information may still be obtained from post-mortem examinations, and histopathology, in many instances.
• A significant degree of post-mortem autolysis will limit the utility of histological examinations. However, depending on the disease, useful information may still be obtained, although extra care will be required in handling the softened tissues.

Additional considerations 

• In certain cases, particularly legal cases where there is expected to be penetrating ballistic injury (eg air rifle pellets) prior radiographs or CT may be useful in narrowing down the anatomic location of such ammunition. You should be mindful of the additional costs associated with these techniques. 
• CT may be used as an ancillary diagnostic tool, but it should not be used to replace a full and methodically performed postmortem examination. 
• In cases of abortion, stillbirth or neonatal death, examination of the placenta is key, so it should be retained, and samples fixed and frozen. Any additional information derived from placental swabs or fresh tissue for bacteriology/mycology are extremely useful in these investigations.

Risk assessment

• Consider and minimize health risks to veterinarian and other animals. If there is a potential for the presence of a zoonotic disease, eg tuberculosis, leptospirosis, weighing up of the risks versus the benefits should be undertaken.
• Consider and minimize health risks to owner if returning animal to client after examination. In most cases, the carcass is not returned to the owner following a complete post mortem, though ‘cosmetic post mortems’ can be performed, although they are often more limited in their investigations.
• Consider and minimize health risks associated with formalin or other fixatives (avoid skin contact, eye contact, inhalation of fumes, and ensure correct labeling of containers).