Re: AFB control tissue

<< Previous Message | Next Message >> (Wenk, Lee & Peggy)
To:Cynthia Favara <>
Date:Tue, 16 Mar 1999 20:35:37 -0500
Content-Type:text/plain; charset=us-ascii

Thanks for the warm fuzzy. 

This was probably the workshop on histology and immunology 
controls given by myself and Maray Weirauch at several NSH S/C. 
We have also been accepted to give the workshop again at
the 1999 NSH S/C in Rhode Island. I don't remember what day.

Also, if anyone is interested, Maray and I will be giving
a teleconference on immunology control on April 21, 1999.
Contact NSH (301/262-6221) for more information.

As to making micro-organism controls:

1. Get some fresh autopsy lung from a patient who died
of something unrelated to infectious lung diseases. It
works better if the person has not been dead very long,
so there is less post-mortem bacterial growth. It also
seems to work a little better if there is a little
fluid in the alveolar spaces, but a nice normal lung
works well.

2. Cut the tissue into small ( <3 x 3 mm square) pieces,
using clean instruments and board. It does not have to
be sterile, but you don't want to contaminate the tissue
with other organism or with fixative.

3. Take the tissue pieces to microbiology (Warn them
first that you are coming. Also, talk with the supervisor
days in advance, to make certain they are agreeable to
do this.)

They can set up a tube with appropriate liquid culture media, 
add the appropriate microorganism (AFB, gram +, gram -, 
spirochete, fungus, etc.). Incubate overnight. Next morning,
add fixative. I usually wait about 30 minutes, then dump
out the incubating medium/fixative mixture, and put on
new fixative. The first has been diluted with the incubating

4. Place fixed tissue in cassettes. Process as usual. 
Embed, section, stain.

The microorganisms will be found inside the alveolar spaces.
There will NOT be inflammatory reaction seen in the tissue.
However, you do have microorganism IN tissue that has been 
processed the SAME as your patient's tissue. THAT is what is 

NOTE: Check with microbiology as to the type of microorganism
they are willing to use. For example, ours will supply a
non-pathogenic AFB, but not TB. However, AFB is AFB, at
least as far the Kinyoun or Ziehl-Neelsen stain is concerned.
So if you HAVE to have have TB, this may be a problem.

Hope this is of help.

Peggy Wenk, HTL(ASCP)
William Beaumont Hospital
Royal Oak, MI 48073

<< Previous Message | Next Message >>