[Histonet] AFB Controls

[Lee & Peggy Wenk]

Make your own.

Take some fresh lung (slightly edematous is better, if you can get it). Cut 
into 2x2 mm cubes (or largest 3x3 mm cubes).

Contact Microbiology, and have them make a broth with a non-pathogenic AFB 
in a large tube (e.g., plastic centrifuge tube). Put lung cubes in broth. 
Incubate overnight (I found that room temp is usually OK).

Next morning, add 10% NBF. Wait about an hour or so, then dispose of NBF, 
and add fresh 10% NBF.  (The first NBF is diluted by the broth, and by 
allowing the NBF to sit in the broth for a while, it kills the bacteria. 
Adding the 2nd NBF allows the tissue to be fixed in 10% NBF, rather than 
diluted NBF.)

Allow to fix most of the day, put tissue in cassettes, process as usual, 
embed, and you have lots of AFB controls for really cheap. Write up a cost 
containment (how much it cost you to make X number of blocks that you can 
get Y number of control slides from vs. the cost of buying the same number 
of Y slides from a vendor.) Management will love you for your cost 
containment.

Works for gram +, gram -, and fungus (get the correct broth). Will work for 
spirochete too, but our micro lab has only a LARGE non-pathogenic 
spirochete, which is much larger than syphilis. So doing a Steiner stain 
would most likely yield a false-negative. (When the large spirochetes 
control is seen, the little syphilis would not be stained.)

Please realize, these controls may not work for IHC. Better check on the 
genus. They work great for Kinyoun/Ziehl-Neelsen/Fites, Brown and 
Hopps/Brown and Brenn, GMS/PAS, Steiner/Warthin-Starry.

Peggy Wenk, HTL(ASCP)SLS

-----Original Message----- 
From: Cheryl
Sent: Thursday, October 10, 2013 5:24 PM
To: histonet <@t> lists.utsouthwestern.edu
Subject: [Histonet] AFB Controls

Help?

We are about to run out of AFB control slides and haven't had a good loaded 
case in a while.  Is there an easy way to come up with an AFB positive block 
or could someone lend me one to be replaced at a later date? (Go through too 
many to be cost effective to buy)

OR is there something out in the world I can use to make a control?

Please respond to tkngflght <@t> yahoo.com

Cheryl Kerry, HT(ASCP)

281.852.9457 Office
800.756.3309 Phone & Fax
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