On receipt at the laboratory the sample is removed and examined. Any lesions can be identified. For example, in this piece of liver a white cystic structure is identified at one edge, so that the tissue can be sectioned to include the lesion and the adjacent normal tissue .. In this normal cat kidney, sectioned longitudinally a thin slice cut at a right angle will demonstrate the cortex and medulla when processed.
The chosen sample, in this case liver, is prepared . (this is about 20x10x3 mm) so that it can be placed into a plastic cassette . and given a unique number ready for processing.