simon monard/purity of sort

From: Pizzo,Eugene (Pizzo@nso1.uchc.edu)
Date: Fri Nov 02 2001 - 12:20:46 EST


Simon,

I have a question about your question, not an answer I'm afraid.

If I understand Volker Eckstein accurately,

"When passing the laser
light, weak fluorecent cells may loose fluorescence by bleaching. Therefore
reanalyses often show the sorted cells not fit the sort gate again. And if
the desired population was close to the negative unwanted ones it is
possible that during reanalyses the fluorescence of the sorted cells fall
into the negatives.
The only argument is loss of fluorescence during the sort."

-then this would suggest that when sorting a 'shoulder' you extend the
sorting region partially into the shoulder(further right) to help exclude
weaker
positives, at least in order to improve purity regardless of whether
those negatives upon reanalysis, were actually once weak positives.
This I do in any case on the supposition that the accuracy of the
sort region is never absolute due to a number of factors especially
the inherent lack of resolution due to stream in air.

But I thought your question was asking whether one could extrapolate
the curve of the shoulders left side distribution into the negative peak,
mathematically and then perform statistics on that extrapolated peak
to assess purity.

Perhaps I read it wrong?

Gene/UCONN Health



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