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[Microbiology] Re: Filtration problem

Bob bbx107 at excite.com.XXXX
Tue Aug 16 22:05:24 EST 2005

On 16 Aug 2005 13:41:33 -0700, "Sly_76" <sylvaincyr at hotmail.com>

>I need to perform a sterility test by filtration (USP 71) on a solution
>containing some particles (transport solution from fresh heart
>recovered for heart valves transplant). So the particles seems to be
>red blood cell, some proteins, lipids and all kind of stuff like that.

That is very unclear. RBC are "big" and will collect on any reasonable
filter. Proteins, lipids "and all that kind of stuff" (means what ??)
are soluble, and will go thru anything.

>The initial solution is Ringer's Lactate solution (isotonic solution).
>My problem is the .45um filter clogged. I tried a 20um prefilter but
>the .45um clogged again. Then I tried 10um prefilter I was able to
>filter 50ml (but i wish to filter 100ml). But if I use 10um or smaller
>pore size filter, I will catch bugs (bacteria, fungi, mold) in the 10um
>instead of the .45um (which one will be placed in broth for sterility
>testing)... I will have to place in culture both filter... or what?...
>What do you think about it?

Is this for a research lab, or an actual medical use? Seems to me
there would be an official procedure for actual medical use.

I'd be surprised if there was much difference in capture of bugs by 10
vs 20 um pre-filters.


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