Summary: FACScan Side Scatter Problems
Carol Oxford (cloxford@ucdavis.edu)
Wed, 3 Jan 1996 13:49:32 -0800
First, thanks to all of you who responded to my problem. Since it
took almost two weeks of continuous troubleshooting to finally solve the
problem, I was desperately seeking a solution and hoped that someone else
out there was seeing the same thing. Since the solution turned out to be
rather unique, I decided to send a message and let you all decide how
relevant it may be to the group. We finally figured out what was happening
by having myself, our BD technical service person, and BD's on-line service
people (via modem) watch as data was acquiring. What looked like a change
in SSC detection was actually a FSC problem! During acquisition, the FSC
scale was changing from linear to log, causing the events to temporarily
acquire on a FCS log scale. The actual scale on the screen would not
change, just the data mode on the machine, so it looked like the events
were dropping relative to side scatter. (It's kind of hard to picture
until you try it!) Our technical rep did an electronic bypass on our FCS
board, so we are unable to run the machine with FSC in log scale, but we
are not having the acquisition problem anymore. BD is working on a more
permanent solution.
Some of the suggestions were to gate out the events that acquired
during this blip since they fell below the normal lymphoid population, but
it definitely changed my percentages. As the machine shifted from linear
to log, monocytes and granulocytes would temporarily acquire in the
lymphocyte gate, so my only option was to re-acquire. Since this "blip"
would occur sometimes in as many as 1 in 4 samples, this option was not
very convenient. Anyway, the BD on-line troubleshooting was great, and
once we got the link established it didn't take them more than a day to
figure out what the problem was.
Anyway, I hope this is helpful. Maybe I can spare another lab a
couple of weeks of "down time!"
Carol
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Carol Oxford _| _| _|_|_|_| _|_|_|
Medical Pathology Flow Cytometry Lab _| _| _| _| _|
University of California _| _| _| _| _|
Davis, California 95616 _| _| _| _| _|
(916) 752-7205 _| _| _| _| _|
(916) 752-4548 fax _|_|_|_| _|_|_|_| _|_|_|
cloxford@ucdavis.edu
University of California, Davis
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