Immunohistochemistry validation is much more than simply 20 positives and 20 negative cases, though this will allow you to meet most accreditation requirements.
Validation is a multi step process: 1. Optimisation: following a thorough literature review (what should and should not stain, clones used (any difference), recommended assay conditions (eg antigen retrieval type), choose an appropriate control to confirm staining conditions and perform an optimum titre. 2. Validation: based on the literature review, choose appropriate known (or expected) positives and negative cases that the pathologists would entertain in the differential diagnosis that should be negative. Take Prostate Specific Antigen as an example, include known prostatic carcinomas with a mix of well, moderately and poorly differentiated prostatic carcinomas and include negative tumours that should not express PSA (eg melanomas, lymphomas, colonic and lung carcinomas). This is a scientific approach that inspires confidence in the usefulness of the test. 3. Another task that we find extremely useful is on-going Verification, where we compare staining results with final diagnosis of cases immunostained for the marker. Food for thought? Regards Tony Henwood JP, MSc, BAppSc, GradDipSysAnalys, CT(ASC), FFSc(RCPA) Principal Scientist, the Children's Hospital at Westmead Adjunct Fellow, School of Medicine, University of Western Sydney Tel: 612 9845 3306 Fax: 612 9845 3318 Pathology Department the children's hospital at westmead Cnr Hawkesbury Road and Hainsworth Street, Westmead Locked Bag 4001, Westmead NSW 2145, AUSTRALIA -----Original Message----- From: Nancy Schmitt via Histonet [mailto:histonet@lists.utsouthwestern.edu] Sent: Wednesday, 25 October 2017 4:16 AM To: 'histonet@lists.utsouthwestern.edu' Subject: [Histonet] validation Good Day! When performing validation on IHC, we use 20 positives and 20 negative cases. When testing for negative, can the normal tissue surrounding the tumor be counted as negative? Does the negative tissue need to be tumor that is negative for the AB or just normal tissue? Thank you for your consideration, Nancy Dubuque, IA Ph. 563-589-9810 NOTICE: This email may contain legally privileged information. The information is for the use of only the intended recipient(s) even if addressed incorrectly. If you are not the intended recipient, please notify the sender that you have received it in error and then delete it along with any attachments. Thank you. NOTICE: This email may contain legally privileged information. The information is for the use of only the intended recipient(s) even if addressed incorrectly. If you are not the intended recipient, please notify the sender that you have received it in error and then delete it along with any attachments. Thank you. _______________________________________________ Histonet mailing list Histonet@lists.utsouthwestern.edu http://lists.utsouthwestern.edu/mailman/listinfo/histonet This message is intended for the addressee named and may contain confidential information. If you are not the intended recipient, please delete it and notify the sender. Views expressed in this message are those of the individual sender, and are not necessarily the views of NSW Health or any of its entities. _______________________________________________ Histonet mailing list Histonet@lists.utsouthwestern.edu http://lists.utsouthwestern.edu/mailman/listinfo/histonet
