Re: Flow Cells

From: Alice L. Givan (Alice.L.Givan@Dartmouth.EDU)
Date: Tue Sep 23 1997 - 08:51:50 EST


Hello Flowers,
Thanks for your answers about BD FACScan flow cell longevity.  Responses varied
(as usual).  There were 18 replies.

At one extreme,  there were about ten  people who had scans vintage 1988-90 and
had never had a flow cell replaced. At the other extreme,  there was one group
with a flow cell that had been replaced 4 times since 1988.  In the middle, 
there were several groups who had flow cells that  had lasted 4-6 years.

I didn't have enough information to correlate  longevity with hrs of use or
with cleaning routines.  A few questions were raised:
1) Do we (or does BD) have a standard test for when a flow cell needs
replacement?  People running small beads (eg calibrite beads) or small
particles (eg platelets) will notice noise from a flow cell and find it
troublesome before groups running only leukocytes.  Is there a standard amount
of noise that is acceptable at standard FSC settings (eg Neal Benson suggests
"With a tube of filtered sheath buffer installed on the sample port, high flow
rate, E01 and 1.00 as FSC Detector/Gain levels, and FSC threshold=52, we
consistently get "background" counts averaging less than 1 event/sec).
2) The underlying theme to most replies is that a rigorous cleaning routine
helps to maintain flow cell longevity and therefore the assumption seems to be
that the noise that develops with time is related to a dirty flow cell. Our
service engineer has implied that flow cells start to get noisy because of
degradation at construction joints.  I am not sure whether this degradation
would be hastened by excessive cleaning with bleach.....
3)  There were some sardonic comments that longevity of flow cells might be
related to whether or not instruments were under service contract.  This could
be interpreted to mean that instruments under service contract received better
preventive maintenance from trained engineers (or that engineers tried harder
to stretch flow cells when BD was having to pay for the replacement).  Last I
checked,  new flow cells were cheaper than service contracts.......so maybe a
next subject for discussion would be the pros and cons of service contracts.

Thanks again.
Alice 
Alice L. Givan
Englert Cell Analysis Laboratory
Dartmouth Medical School
Lebanon,  New Hampshire
NH 03756 USA
tel 603-650-7661
fax 603-650-6130
e-mail givan@dartmouth.edu



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