<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META http-equiv=Content-Type content="text/html; charset=iso-8859-1">
<META content="MSHTML 6.00.2800.1264" name=GENERATOR>
<STYLE></STYLE>
</HEAD>
<BODY bgColor=#ffffff>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN class=500201522-08102003>In my
opinion you should always run a negative control with every patient run. For
starters, how do you know</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN class=500201522-08102003>a.
Your blocking solutions have worked?</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN class=500201522-08102003>b. You
haven't got endogenous biotin activity (especially in liver biopsies) giving a
false positive?</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN class=500201522-08102003>c. You
haven't got a contaminant?</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN
class=500201522-08102003></SPAN></FONT> </DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN class=500201522-08102003>For
clinical assurance and governance reasons alone I would have thought that
negative controls are essential.</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN class=500201522-08102003>I
think the reasons for DAKO selling the two reagents separate is for
commercial reasons only (they can charge more) rather than any fact that people
aren't using them.</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN
class=500201522-08102003></SPAN></FONT> </DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN class=500201522-08102003>In the
UK it is considered "best practice" to use negative controls and not to do so
would be frowned upon by the National External Quality Assurance Scheme (NEQAS)
who monitor the quality of immuno carried out by hospitals in the UK, which
nearly every lab in the UK and many more overseas are signed up
to.</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN class=500201522-08102003>No
negative controls is poor quality control in my book.</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN
class=500201522-08102003></SPAN></FONT> </DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN class=500201522-08102003>Nick
Kirk</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN
class=500201522-08102003>Histopathology</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN
class=500201522-08102003>Hinchingbrooke Hospital</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN
class=500201522-08102003>Huntingdon</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN
class=500201522-08102003>England</SPAN></FONT></DIV>
<BLOCKQUOTE dir=ltr style="MARGIN-RIGHT: 0px">
<DIV class=OutlookMessageHeader dir=ltr align=left><FONT face=Tahoma
size=2>-----Original Message-----<BR><B>From:</B>
histonet-admin@lists.utsouthwestern.edu
[mailto:histonet-admin@lists.utsouthwestern.edu]<B>On Behalf Of
</B>vermast<BR><B>Sent:</B> 08 October 2003 21:57<BR><B>To:</B>
histonet@lists.utsouthwestern.edu<BR><B>Subject:</B> [Histonet] negative IHC
controls<BR><BR></FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>I would like to get a feel for how many out there
are running negative control slides for IHC. </FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>In our lab we do just a handful of antibodies and
initially I had been running a negative control slide with each patient slide.
After much discussion with our pathologists, we decided to omit these
negatives (which were conistently negative) and continue to just run a
positive control with each primary antibody for the run. We use the Dako
autostainer and prediluted primaries. The decision to stop running
negatives also coincided with Dako's decision to sell the negative control
sera separately from the primaries (they used to come packaged
together). Perhaps I assumed that discontinuing to pair these reagents
together meant that few labs were using the negatives.</FONT><FONT face=Arial
size=2></DIV></FONT>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Anyhow, after having reviewed the last QMPLS
(Canada) survey committee comments, I believe the committe would like a
negative control run with each patient tissue slide in order to evaluate
background (they have used NCCLS guide pages as reference).
Incidentally we weren't a part of the survey due to a
technicality.</FONT></DIV>
<DIV><FONT face=Arial size=2>Any help or advice would be
appreciated.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>L. Vermast</FONT></DIV>
<DIV><FONT face=Arial size=2>Stratford,
Ont.</FONT></DIV></BLOCKQUOTE></BODY></HTML>