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Theoretically, I agree with you that (a) running multiple negative=20
control sections to cover the different antibodies/pretreatments is=20
ideal and (b) money should be well spent on QC (I can't emphasize that=20=

enough). However, I honestly don't remember when was the last time when=20=

I had a false positive staining on a patient's slide that the negative=20=

control was the only way that allowed me to recognize the false=20
positive signal on the real slide. And we look at 100s of IHC stains=20
every day.

Experienced pathologists and technologists can still recognize in > 99%=20=

of the times a false positive signal from a real signal on the tissue=20
section of a given antibody without even having to look at negative=20
controls. I don't think it should be a CAP requirement at all. In fact,=20=

I'd say the same thing on positive controls. All you need is one=20
positive control per antibody, but not one control/per antibody/per=20
patient. In many cases positive internal controls are present on the=20
same slide, so you can tell whether your antibody worked simply by=20
evaluating the expected positive internal controls. In fact, if your=20
positive 'external' control worked and internal controls didn't, then=20
you need to repeat your antibody test regardless of the positive=20
external control. External controls are different tissues, fixed=20
differently, processed differently and the tissue ages differently (in=20=

terms of its antigenicity).

Individuals who perform and interpret IHC studies must have the=20
knowledge to recognize the expected sub-cellular localization of every=20=

antibody on every type of tissue, including aberrant signals. For=20
instance, you can easily dismiss a granular cytoplasmic TTF-1 signal as=20=

not positive, because TTF-1 is a nuclear transcription factor and we=20
know it's expressed in the nuclei. However,  hepatocellular carcinomas=20=

can give you a consistent and reproducible granular and cytoplasmic=20
TTF-1 signal, and if you subsequently run confirmatory markers=20
(HepPar1, polyclonal CEA, CD10, etc.) they will be positive. Such=20
(granular cytoplasmic) signal should be recognized by the interpreter=20
(tech or pathologist) as a specific signal for  tumors with hepatoid=20
phenotypes. This is just one of many examples..

The bottom line: in real life, one negative control per case is more=20
than sufficient. And to say the least, it's inaccurate to state this is=20=

poor patient care and lousy quality control.

I look forward to any constructive criticism.

Hadi Yaziji, M.D.
PhenoPath Laboratories

On Thursday, October 9, 2003, at 07:03  AM, Horn, Hazel V wrote:

> Not only should you be running a negative control for each patient=20
> slide.=A0=A0 That negative control should be treated just as your =
antibody=20
> is.=A0=A0 If the antibody is rabbit and antigen retrieved, so should =
your=20
> control.=A0=A0 If another antibody on the same patient is mouse and =
not=20
> retrieved another negative control should be run with this same=20
> protocol.=A0=A0 In the United States, labs that are inspected by the =
CAP,=20
> are required to run these controls.=A0=A0=A0 MONEY should never be=20
> considered as a reason to stop doing a part of a procedure.=A0=A0 It's=20=

> poor patient care and lousy quality control.=A0=A0 IMHO.
> =A0
> Hazel Horn, HT/HTL (ASCP)
> Histology Supervisor
> Arkansas Children's Hospital
>
> Phone - 501.364.4240
> Fax - 501.364.3912
>
>
> -----Original Message-----
> From: vermast [mailto:vermast@rogers.com]
> Sent: Wednesday, October 08, 2003 3:57 PM
> To: histonet@lists.utsouthwestern.edu
> Subject: [Histonet] negative IHC controls
>
> =A0
> I would like to get a feel for how many out there are running negative=20=

> control slides for IHC.=A0
> =A0
> In our lab we do just a handful of antibodies and initially I had been=20=

> running a negative control slide with each patient slide. =A0 After =
much=20
> discussion with our pathologists, we decided to omit these negatives=20=

> (which were conistently negative)=A0and continue to just run a =
positive=20
> control with each primary antibody for the run.=A0 We use the Dako=20
> autostainer and prediluted primaries.=A0 The decision to stop running=20=

> negatives also coincided with Dako's decision to sell the negative=20
> control sera separately from the primaries (they used to come packaged=20=

> together).=A0 Perhaps I assumed that discontinuing to pair these=20
> reagents together meant that few labs were using the negatives.
> =A0
> Anyhow, after having reviewed the last QMPLS (Canada) survey committee=20=

> comments, I believe the committe would like a negative control run=20
> with each patient tissue slide in order to evaluate background=A0 =
(they=20
> have used NCCLS guide pages as reference).=A0 Incidentally we weren't =
a=20
> part of the survey due to a technicality.
> Any help or advice would be appreciated.
> =A0
> L. Vermast
> Stratford, Ont.
>
>
>
>
>

>
> The information contained in this message may be privileged and=20
> confidential and protected from disclosure. If the reader of this=20
> message is not the intended recipient, or an employee or agent=20
> responsible for delivering this message to the intended recipient, you=20=

> are hereby notified that any dissemination, distribution or copying of=20=

> this communication is strictly prohibited. If you have received this=20=

> communication in error, please notify us immediately by replying to=20
> the message and deleting it from your computer. Thank you. Arkansas=20
> Children's Hospital

--Apple-Mail-8--516027199
Content-Transfer-Encoding: quoted-printable
Content-Type: text/enriched;
	charset=ISO-8859-1

Theoretically, I agree with you that (a) running multiple negative
control sections to cover the different antibodies/pretreatments is
ideal and (b) money should be well spent on QC (I can't emphasize that
enough). However, I honestly don't remember when was the last time
when I had a false positive staining on a patient's slide that the
negative control was the only way that allowed me to recognize the
false positive signal on the real slide. And we look at 100s of IHC
stains every day.=20


Experienced pathologists and technologists can still recognize in >
99% of the times a false positive signal from a real signal on the
tissue section of a given antibody without even having to look at
negative controls. I don't think it should be a CAP requirement at
all. In fact, I'd say the same thing on positive controls. All you
need is one positive control per antibody, but not one control/per
antibody/per patient. In many cases positive internal controls are
present on the same slide, so you can tell whether your antibody
worked simply by evaluating the expected positive internal controls.
In fact, if your positive 'external' control worked and internal
controls didn't, then you need to repeat your antibody test regardless
of the positive external control. External controls are different
tissues, fixed differently, processed differently and the tissue ages
differently (in terms of its antigenicity).=20


Individuals who perform and interpret IHC studies must have the
knowledge to recognize the expected sub-cellular localization of every
antibody on every type of tissue, including aberrant signals. For
instance, you can easily dismiss a granular cytoplasmic TTF-1 signal
as not positive, because TTF-1 is a nuclear transcription factor and
we know it's expressed in the nuclei. However,  hepatocellular
carcinomas can give you a consistent and reproducible granular and
cytoplasmic TTF-1 signal, and if you subsequently run confirmatory
markers (HepPar1, polyclonal CEA, CD10, etc.) they will be positive.
Such (granular cytoplasmic) signal should be recognized by the
interpreter (tech or pathologist) as a specific signal for  tumors
with hepatoid phenotypes. This is just one of many examples..


The bottom line: in real life, one negative control per case is
more than sufficient. And to say the least, it's
inaccurate to state this is poor patient care and lousy quality
control.


I look forward to any constructive criticism.=20


Hadi Yaziji, M.D.

PhenoPath Laboratories


On Thursday, October 9, 2003, at 07:03  AM, Horn, Hazel V wrote:


Comic Sans =
MS0000,0000,FFFFNot
only should you be running a negative control for each patient
slide.=A0=A0 That negative control should be treated just as your =
antibody
is.=A0=A0 If the antibody is rabbit and antigen retrieved, so should =
your
control.=A0=A0 If another antibody on the same patient is mouse and not
retrieved another negative control should be run with this same
protocol.=A0=A0 In the United States, labs that are inspected by the =
CAP,
are required to run these controls.=A0=A0=A0 MONEY should never be
considered as a reason to stop doing a part of a procedure.=A0=A0 It's
poor patient care and lousy quality control.=A0=A0 =
IMHO.

=A0

Hazel Horn, HT/HTL (ASCP)

Histology Supervisor

Arkansas Children's Hospital


Phone - 501.364.4240

Fax - 501.364.3912



Tahoma-----Original Message-----

From: vermast [mailto:vermast@rogers.com]

Sent: Wednesday, October 08, 2003 3:57 PM

To: histonet@lists.utsouthwestern.edu

Subject: [Histonet] negative IHC controls


=A0

ArialI would like to get a feel
for how many out there are running negative control slides for =
IHC.=A0

=A0

ArialIn our lab we do just a
handful of antibodies and initially I had been running a negative
control slide with each patient slide. =A0 After much discussion with
our pathologists, we decided to omit these negatives (which were
conistently negative)=A0and continue to just run a positive control with
each primary antibody for the run.=A0 We use the Dako autostainer and
prediluted primaries.=A0 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).=A0
Perhaps I assumed that discontinuing to pair these reagents together
meant that few labs were using the negatives.

=A0

ArialAnyhow, 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=A0 (they have used NCCLS guide
pages as reference).=A0 Incidentally we weren't a part of the survey due
to a technicality.

ArialAny help or advice would be
appreciated.

=A0

ArialL. =
Vermast

ArialStratford, =
Ont.






<



The information contained in this message may be privileged and
confidential and protected from disclosure. If the reader of this
message is not the intended recipient, or an employee or agent
responsible for delivering this message to the intended recipient, you
are hereby notified that any dissemination, distribution or copying of
this communication is strictly prohibited. If you have received this
communication in error, please notify us immediately by replying to
the message and deleting it from your computer. Thank you. Arkansas
Children's Hospital

=

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