Diana: The most simple answer to your question is: "Because that is the way it has been done for more than 150 years". The second question would be: "Is it necessary?" and the short answer to this question is: NO!!! As a matter of fact, one of the steps I have developed to totally eliminate xylene from the histology lab refers to the "clearing" of stained sections, not only "special stains" (the so called HC and IHC) but the routine as well (the H&E). Now, the "secret" to a successful drying of the stained slides is NOT to let them air dry because that will take not only too much time, but you can never be sure if the section is completely dry and if you add the mounting medium to a not completely dried section, you will have transparency problems. The correct way of doing that is by drying the stained sections during 5 minutes at 60ºC in an oven. Under separate cover I am sending you something I published about your question and other aspects of how to completely eliminate xylene from ALL steps in the histology laboratory. René J.
________________________________ From: Diana McCaig <dmcc...@ckha.on.ca> To: histonet@lists.utsouthwestern.edu Sent: Tuesday, September 11, 2012 10:32 AM Subject: [Histonet] air drying special stain slides rather than dehydrate and clear I was hoping to get information on why special stains are dehydrated, cleared and mounted vs allowing them to be blotted dry, air dried then coverslip. Every procedure I have ever encountered always indicates to dehydrate and clear but I have heard where some labs are blotting the slides , allowing to air dry (probably not set standard time) and dipped in xylene prior to cover slipping. Reason given is that the counterstain gets washed out. Wouldn't adjusting the times be a better resolution. I understand residual water could be present and cause long term issues on storage but wanted some other opinions on this process. Diana _______________________________________________ Histonet mailing list Histonet@lists.utsouthwestern.edu http://lists.utsouthwestern.edu/mailman/listinfo/histonet _______________________________________________ Histonet mailing list Histonet@lists.utsouthwestern.edu http://lists.utsouthwestern.edu/mailman/listinfo/histonet
