[Histonet] RE: How long should autopsy/necropsy tissue be in fixation for a suspected TB case?

[Jay Lundgren]

     As long as possible.  I remember reading somewhere about TB in lung
tissue that was still viable after *years* of 10% NBF.  Make sure the lungs
are thoroughly perfused, or they will still be unfixed in the middle.  There
is a technique to "inflate" lungs at autopsy using a large syringe full of
NBF and a clamp.  Make sure that the specimen is not contacting the walls or
bottom of the specimen container.  You can suspend the whole organ with
string inside the container, if needed. One can also use gauze or paper
towels to keep the organ under the surface of the fixative.  Lung tissue is
notoriously difficult to fix properly, due both to the high lipid content of
the pleural parenchyma, and the fact that fresh lungs float.

                                                                Sincerely,

                                                                      Jay A.
Lundgren, M.S., HTL (ASCP)