Diana, Obviously there are no negative controls for some special stains because they just stain tissue elements (ie, trichrome) that are often in all tissues and we are just looking at the morphology changes in a disease state. A negative would have you apply the stain to tissue that could not be stained by the stain, or not apply the specific stain to show there is no interference from other reagents used. The question is whether that is useful for tinctorial stains.
The solution to these is to put some verbiage in your procedure that this does not require a negative control and why. You should have clear description, and pictures of what an acceptable stain looks like, and even more important, what a failed stain looks like. However, a negative should be used for organism stains, and could be useful for some specific tissue elements. For example, congo red or iron, you can leave off the specific stain and just use the counter stain (it could be useful - if the control is cut thru for instance the positive and negative would look the same). I know well that this is not the normal practice going back many decades, and we argued with the Joint Commission about this as well, but regulatory agencies are becoming stricter about validations and controls, so it could be a good thing to prove your systems work as intended and to catch the rare failure. Tim Morken Pathology Site Manager, Parnassus Supervisor, Electron Microscopy/Neuromuscular Special Studies Department of Pathology UC San Francisco Medical Center Good day, I have a question that hopefully I can get help: We are preparing for our CAP Inspection for 2016. The ANP: 21395 requirements states: For special stains, including histochemical stains, and studies using immunologic and FISH/ISH methodology, positive and negative controls are verified and recorded as acceptable prior to or concurrent with the reporting of patient results and records maintained. Evidence of Compliance: Records for verification of control acceptability (prior to completion of associated cases) What I understand from this requirement is not only do they want a positive control compliance but also a negative control compliance for special stains, so if we need a negative controls for special stains how do you go around doing a negative control? Do we use a tissue not specific for the special stain such as an Congo Red using a tissue without amyloid or eliminate a reagent from the protocol? Please help! Thanks! Diana Martinez-Longoria Bachelors of Science in Biology Histotechnician (ASCP)cm El Centro Regional Medical Center Phone: 760-339-7267 Fax: 760-339-4570 Email:dmlongoria at ecrmc.org<http://lists.utsouthwestern.edu/mailman/listinfo/histonet> _______________________________________________ Histonet mailing list Histonet@lists.utsouthwestern.edu http://lists.utsouthwestern.edu/mailman/listinfo/histonet
