[Histonet] False positive AFB

[Poteete, Jacquie A.]

As an old Medical Technologist turned IHC Technologist, yes, it is necessary
to order an acid fast culture.  Those bugs won't grow on the routine culture
media.  They also require more time to grow, so don't expect the Micro folks
to give you a report in just a few days.

Jacquie Poteete MT(ASCP), Lead Technologist, IHC Laboratory
Saint Francis Hospital, Tulsa, OK
japoteete <@t> saintfrancis.com


> -----Original Message-----
> From:	Claye Clyatt [SMTP:CCLYATT <@t> mail.mcg.edu]
> Sent:	Thursday, December 11, 2003 8:21 AM
> To:	FreidaC <@t> aol.com; histonet <@t> lists.utsouthwestern.edu
> Subject:	Re: [Histonet] False positive AFB
> 
> Freida,
> 
> Would it not be wise to identify AFB contamination in one's water
> source?  If contamination is present, I think it could be assumed that
> AFB contamination could also enter the specimen by fixation and
> processing in house made 10% formalin, alcohol dilutions, etc.  I
> routinely culture our deionized water once a month.  Not being a
> microbiologist, I'm not sure if I'm eliminating the possibility of AFB
> contamination by only routine culture.  Do I need to request an AFB
> culture?
> 
> Claye
> 
> Claye Clyatt
> Chief Histotechnologist
> Department of Pathology 
> Room #BF119
> Medical College of Georgia
> Augusta, Ga 30912
> office   (706) 721-3630
> pager  (706) 721-7243-1132
> e-mail: cclyatt <@t> mail.mcg.edu
> 
> 
> >>> <FreidaC <@t> aol.com> 12/11/03 08:57AM >>>
> 
> From personal experience I do know that acid fast organisms are present
> in 
> some tap water.  We cultured them from water after some bad experiences
> with 
> false positives.  Wang reported that somewhere over 30% of water
> fountains showed 
> the presence of acid fast organisms (non-pathogens, but who can tell
> the 
> difference on a stained slide).  This was done using the fluorescence
> technique.  
> As a consequence, we filtered our water bath water through a Millipore
> filter 
> after it was already passed through a charcoal filter and a deionizing
> column. 
>  We also used no tap water prior to the carbol-fuchsin and we ran a
> negative 
> control (uterus - extra cuts from blocks as the routine H&Es were cut) 
> from 
> the same days workload with each batch of AFB slides.   So take care
> with your 
> AFB stains.
> 
> Freida Carson
> 
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