[Histonet] safranin for marking small specimens

[rsrichmond <@t> aol.com]

Marking small biopsy specimens so that the embedder can find them after processing - this question has been raised several times on Histonet, particularly since a favorite marking dye, Mercurochrome, is no longer available. 

Recently in my travels I've found a service that uses safranin for this purpose. The tissue is put on lens paper or on a blue biopsy foam pad, and the dye is dabbed onto the tissue with the tip of a wooden applicator stick. Tissue is easily visible to the embedder, and is visible in the finished paraffin block.

The technique is particularly valuable on this pathology service, where both the pathologists (including me!) and the histotechnologist have elderly eyes, illumination is insufficient, and magnification is not available.

We're not talking about marking margins (india ink and colored inks). The safranin is not visible in the slides.

The safranin solution is the one used as the Gram stain counterstain by the microbiology laboratory, so that nothing new needs to be ordered. Specifically, it's safranin (Colour Index 50240, not saffron) 0.6% w/v, in 20% reagent alcohol.

Bob Richmond
Samurai Pathologist
Knoxville TN
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