[Histonet] IHC validation

Tue Feb 8 17:37:57 CST 2011

When changing instruments you are validating the instrument, not the test. For each antibody you just need to run parallel tests in each instrument showing equivalence. 

However, if you change the instrument and ALSO change the antibody and/or detection system, Antigen retrieval, etc, then you need to revalidate the test.

For most antibodies (Class I FDA exempt, ancillary tests) that involves 5-10 positive and negative cases. A small tissue array can suffice. You should do reproducibility tests for a few antibodies - 5-10 identical slides on one run, 5-10 identical slides on 5-10 runs.

When changing Class II antibodies (ER, PR, Her2) and/or their detection systems you will need to run more extensive test. As Liz says, 40 positive, 40 negative. Again, a tissue array is great for that. 

Changing instruments these days is a big deal when a vendor ties you to their reagents. 

Tim Morken
Supervisor, Histology, IPOX
UCSF Medical Center
San Francisco, CA, USA

-----Original Message-----
From: histonet-bounces <@t> lists.utsouthwestern.edu [mailto:histonet-bounces <@t> lists.utsouthwestern.edu] On Behalf Of Liz Chlipala
Sent: Tuesday, February 08, 2011 3:20 PM
To: Weems, Joyce; Joe Nocito; Histonet
Subject: RE: [Histonet] IHC validation

Nope that's the recommendation for everything, in the paper they state
additional development is required for prognostic markers. Once you have
validated an antibody it only requires 3 tissues when you get a new lot
number:  1 strong positive, 1 weak to moderate positive and 1 negative.
>From how I read the article its 25 tissues and then 3 tissues, it does
not talk about slides so it is possible to put multiple tissues on one
slide.  Again these are just recommendations; I do not think that there
is a set standard yet.

Liz

Elizabeth A. Chlipala, BS, HTL(ASCP)QIHC
Manager
Premier Laboratory, LLC
PO Box 18592
Boulder, Colorado 80308
office (303) 682-3949 
fax (303) 682-9060
www.premierlab.com

Ship to Address:
1567 Skyway Drive, Unit E
Longmont, Colorado 80504

-----Original Message-----
From: Weems, Joyce [mailto:JWeems <@t> sjha.org] 
Sent: Tuesday, February 08, 2011 4:13 PM
To: Liz Chlipala; Joe Nocito; Histonet
Subject: RE: [Histonet] IHC validation

But that is for receptors, correct? Do you do that for everything? 
Thanks, j 

-----Original Message-----
From: histonet-bounces <@t> lists.utsouthwestern.edu
[mailto:histonet-bounces <@t> lists.utsouthwestern.edu] On Behalf Of Liz
Chlipala
Sent: Tuesday, February 08, 2011 17:58
To: Joe Nocito; Histonet
Subject: RE: [Histonet] IHC validation

Joe

If you are following the recommendations from the CAP paper on IHC
standardization then it would be 25 tissues (10 strong positive, 10 weak
to moderate positive and 5 negative). 

Liz

Elizabeth A. Chlipala, BS, HTL(ASCP)QIHC Manager Premier Laboratory, LLC
PO Box 18592 Boulder, Colorado 80308 office (303) 682-3949 fax (303)
682-9060 www.premierlab.com

Ship to Address:
1567 Skyway Drive, Unit E
Longmont, Colorado 80504

-----Original Message-----
From: histonet-bounces <@t> lists.utsouthwestern.edu
[mailto:histonet-bounces <@t> lists.utsouthwestern.edu] On Behalf Of Joe
Nocito
Sent: Tuesday, February 08, 2011 3:44 PM
To: Histonet
Subject: [Histonet] IHC validation

Greetings Histoland,
I need some help. We are about to switch IHC machines from the
Richard-Allen Axiom to the Ventana Benchmark Ultra. How many slides, per
antibody, do you run for the validation study? We have over 100 primary
antibodies. Normally, when we work up a new antibody, we  start with a
titer. Once that is established, we run 10 cases to check for
specificity. Hopefully we can obtain cases that are really positive,
some weakly positive and some flat out negative. Once that is completed,
we run 10 different tissue types to check for any unexpected
cross-reactivity. 
    The ultra holds 30 slides and we are receiving two machines. If we
run 10 slides/antibody, that's going to take a while, not to mention the
number of detection kits that will be used. Do you think 5
slides/antibody is sufficient? I emailed CAP last week for their take
and they never returned my email (I told my medical director to hold
their check for the year and see how fast they respond to that). Ah oh,
don't go down that road Joe, it's unhealthy. What are your thoughts?
Thanks

Joe (JTT)

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