Collection of Tissue Samples

Tissues are collected for histopathology, parasitology, biochemistry, immunohistochemistery; culture and demonstration of DNA.

For histopathology samples can be preserved by fixation, for all other techniques, fresh samples are required.

The skin may be removed with ordinary equipment, but sterile instruments should be used to open body cavities, dissection and collection of tissue specimens. In the field, instruments can be sterilised conveniently by boiling in a simple instrument steriliser, using a portable LPG source.
Each piece of tissue of about 5g should be placed in a separate, sterile container (e.g. screw-capped jar). Organs can be wrapped in absorbent paper to prevent leaking. Care should be taken not to contaminate tissues with other tissue, body fluids or intestinal contents. 

Sampling boxes should be labeled and the submission forms fill at the time of collection.

Collection of fresh tissue samples 

Samples can be send with bacterial or virus transport medium depending on the diagnostic technique, the nature of the sample and the suspected disease. It is important to contact the laboratory or to refer to the Manual of Standards for diagnostic tests and Vaccines from the OIE to know what medium to use.

Commonly used transport medium include :

• 0.04M phosphate buffer (pH 7.6),
• Glycerol-phosphate buffer.

Samples should be refrigerated at 4°C and sent on ice. Freezing samples is not recommended unless immunohistochemistery is used.

Collection of fixed tissue samples

Tissue samples not more than 1 cm x 2 cm and 5 mm thick should be cut and placed into at least 10 times the volume of neutral buffered formalin. Immunohistochemistery can be done on frozen fixed tissues but samples for histopathology should not be frozen.

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