Cleaning + background events

Frederic Preffer preffer at
Tue Dec 2 13:40:58 EST 1997

do you have the SAME problem on both the FACScan and FACScalibur? We rarely
noticed your problem with our FACScans but do have the problem you state
with the new FACScalibur.

frederic preffer

At 07:59 AM 12/2/97 +0000, you wrote:
>Hello fellow fans of flow!
>I apologise in advance but I would like to return to the ever-popular
>cytometer cleaning question.
>I have a FACScan and a FACS Calibur, both multi-user high throughput
>machines, both used for DNA and for phenotyping experiments. I have
>impressed upon all my users that after running their samples they MUST run
>a cleaning procedure which is:
>1. dH2O 5 mins on high flow
>2. detergent (7X) 5 mins high flow
>3. dH2O 2 mins high flow (if PI has been used I put a 5 min bleach step
>subsequent to this)
>4. Standby (If I am about I tend to leave it on run)
>I also run detergent and dH2O through the entire fluidics system once a
>week. So far so good, rarely get clogs, bead and DNA CVs and profiles
>fine, haven't had to slay too many users for forgetting and I am happy
>(well as happy as I get these days). Recently though I have been informed
>of a few 'problems'. I have one user in particular who quite often ends up
>on the linoleum in a black apoplexy. She is running 3 or 4 colour fetal
>thymocytes. Before she starts her run she acquires 'data' from a tube of
>autoclaved distilled water. Her complaint is that events are acquired that
>fall within her cell gate. question is this:
>Should I expect to see 'cells' in a tube of dH2O? If so, how many, say,
>per minute? I have just run such a tube on high flow rate and got over a
>10 minute period an average of 2-4 events per second (Low and high flow)
>in a typical cell gate. I would be tempted to say that this is
>insignificant in a real sample compared with the cell flow rate.
>Does anyone have a view on what is acceptable (I checked the archives as
>there was a flurry of cleaning correspondence earlier in the year but
>couldnt find the answer!)? Am I wrong in saying that there would never be
>a *totally* clean background?
>Oh I use PBS as sheath fluid and I have changed the in-line filter.
>Thanks in advance!
>*  Derek Davies                       Voice: (44) 0171 269 3394            *
>*  FACS Laboratory,                   FAX: (44) 0171 269 3100              *
>*  Imperial Cancer Research Fund,     e_mail: derek.davies at   *
>*  London, UK                                                              *
>*                                                                          *
>*  Web Page:                *
         Frederic I. Preffer
preffer at
Department of Pathology- Warren 525A
100 Blossom St
Massachusetts General Hospital
Boston MA 02114
  v(617) 726-7481  fax (617) 724-3164

More information about the Cytometry mailing list