Re: Purity of sorted populations

Mike Salmon (salmonm@rheuma.bham.ac.uk)
Mon, 3 Apr 1995 09:15:07 +0000

> From: FACS_COPY@wehi.edu.au
> Date: Fri, 31 Mar 1995 12:37:13 +1000
> Subject: Re: Purity of sorted populations
> To: cytometry@flowcyt.cyto.purdue.edu
EDITED
> But going further from what has already been
> said, I would assert that running faster will not, in itself, lower
> the sort purity if the sorter is doing coincidence checking; it may
> only increase the rate of occurrence of doublet events where a cell,
> negative for the marker you are sorting for, rides along as a
> passenger into the collection tube (hence the benefits of the "dump
> channel" already alluded to). If you are sorting cells which are
> negative for everything, then the only passengers must also be
> negative and there's no reason you can't aim for three-nines (99.9%)
> purity NO MATTER HOW FAST YOU SORT. Going faster should only lower
> the recovery.

The problem is with any machine I have experience of (Coulter and BD)
Going faster DOES reduce purity to a significant extent, co-incidence
abort or not. I agree that sorting completely negative cells is much
easier, but they are even easier to select in greater numbers, faster and
with a similar purity using magnetic beads. For functional studies
beads have the same benefit of minimal biological modification.
Flow sorting is most useful in my opinion for sorting the difficult
stuff

Have fun

Mike

...........................................................
Mike Salmon
Department of Rheumatology
The Medical School
University of Birmingham
Birmingham B15 2TT
United Kingdom
Tel: 44 (0)121 414 6780
Fax: 44 (0)121 414 6794

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