Hello Histonetters:
    My pathologist returned from a meeting with a request for an HBQ stain 
(Hall's and Brunt's Quadruple stain).  One of the components is Direct Red 
(C.I. 28160).  I have done a little research and have discovered that Congo 
Red is also called Direct Red Y, R and C, but the C.I. # is different.  Sigma 
only lists Congo Red in their catalogue and I couldn't locate Direct Red in 
any of my other usual sources.  Can anyone recommend another distributor that 
I might try?  Also, since the procedure calls for a 0.5% aqueous Direct Red 
solution (appears to be a counterstain), what are the chances that 
substituting Congo Red will work? 
    Any input will be greatly appreciated!

Thanks,
Diane

Diane Mahovlic, HT(ASCP)
Orthopedic Pathology and Biomaterials Laboratory
The Cleveland Clinic Foundation
Cleveland, Ohio