AAEP General Recommendations for Diagnostic Sample Handling and Storage for Delayed Submission to a Diagnostic Laboratory

These guidelines are intended to be a reference for veterinarians conducting necropsies and collecting samples in their respective practices. They are neither regulations nor directives and should not be interpreted as such. It is the responsibility of attending veterinarians, along with the clinical histories, and in consultation with their laboratories, to utilize relevant information to determine optimal sample collection and handling protocols.

Overview:

Delayed submission of diagnostic samples from necropsies or other critical diagnostic workups requires correct handling and storage of tissues to ensure samples maintain their diagnostic viability from the time of collection until processing and analysis. When samples cannot be delivered to the laboratory in a timely fashion (<48 hours post procurement), the following recommendations may assist in preserving sample integrity. Some samples, unfortunately, cannot be held without sample degradation, and test results from such samples must be interpreted with caution. Practitioners are encouraged to contact their laboratory for further information and guidance whenever possible.

Ideally, samples should be received in the laboratory within 48 hours of collection. If this is not possible or a laboratory cannot accept samples, collecting 2 full sets of tissues, one for freezing and one for formalin fixation, is a reliable way to preserve samples for the most common diagnostic tests. Photographs should be taken at the time of necropsy and collection to assist with animal identification and to document lesions and findings.

• Temperature for sample refrigeration: 40°F (4°C)
• Temperature for sample freezing: 5°F to 13°F (-15°C to -10°C)

Notes:

• -Use sample containers that can withstand freezing temperatures such as plastic tubes and vials
• -Do not store samples in a self- defrosting freezer due to the freeze-thaw cycle and possible damage to the sample

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