In order to achieve good histology it is important to fix fresh material correctly. Tissues should be fixed in 10 percent neutral buffered formalin (NBF) and placed in a plastic container of suitable size with a wide neck and a tight fitting lid. This 100ml container is ideal for most samples. Containers with narrow necks . should be avoided because it is difficult to remove samples which may have been squeezed in when still fresh.
It is important to use the correct amount of fixative for the size of the sample. Ideally a block of tissue approximately 2x1x1cm should be placed in a pot containing approximately 50-60 ml of fixative. . Larger samples can be fixed provided they are placed in a container in which the volume of fixative is approximately 10 times the volume of the tissues. However, in such cases the centre of the sample may not be fixed and it may be more appropriate to remove a small representative sample. . If considered necessary the large and small pieces could be submitted in plenty of NBF.