Hi Chris,
When this problem has happened in my lab it's been due to one of three
reasons (most common first):
1) The customer spins the cells gently, and discards a proportion in the
supernatant - I try to get people to count the cells before they wash them,
failing this get them to spin them harder than they would normally and
check the supernatant (put it through the sorter if they're reluctant to
look at it).
2) Timing problems where the sort envelope doesn't coincide with the actual
break-off point. You can adjust this using switches in the instrument
console, it doesn't vary too much, and you'll only need to check it
occasionally. The narrower the sort envelope, the greater the sensitivity
to timing errors- how wide is your envelope?
3) High abort rates (due to clumpy cells, nasty pulse shapes or sorting too
fast), can make your counters into liars, particularly in Normal-R mode.
Try sorting and counting beads while varying the parameters for 2 and 3,
but only after you've checked 1 first.
Ray
At 1:35 pm -0800 2/12/99, Chris lena wrote:
>Hello gang,
>My question deals with our FacStar. I am getting reports of counts that are
>about 1/2 of the cell number the instrument says were recovered. I am
>wondering if anyone has seen this or what to do to fix this problem. Cell
>count is very important in many of our studies.
>Thanks in advance and Happy Holidays,
>
>chris
>
>
>
>
>
>Chris Lena
>Laboratory Technician
>La Jolla Institute For Allergy and Immunology
>phone:(858)678-4536
>fax:(858)678-4595
>cali@liai.org
>http://www.liai.org
>
> _ _
> (_)-(_)
> \"/
> =V=
>
>
Ray Hicks
________________________________________________________________________
|University of Cambridge |Tel 01223 330149 |
|Department of Medicine |Fax 01223 336846 |
|Level 5, Addenbrookes Hospital |e-mail <rh208@cus.cam.ac.uk> |
|Hills Road Cambridge |Web http://facsmac.med.cam.ac.uk |
|CB2 |ftp server ftp://131.111.80.78 |
|UK | |
|_________________________________|_____________________________________|
This archive was generated by hypermail 2b29 : Wed Apr 03 2002 - 11:54:18 EST