[Histonet] Re: Paraffin Blocks

Robert Richmond RSRICHMOND <@t> aol.com
Thu Feb 5 16:27:31 CST 2009

How long to retain paraffin blocks (human tissue) is an issue that's
going to need re-thinking.

Presently most pathology services in the USA retain them for no more
than ten years. If the laboratory closes, slides and blocks are
disposed of immediately.

It seems to me that in the coming age of molecular pathology, there
will be a lot more interest in recovering paraffin blocks after longer
periods of time. I think that the regulatory agencies will soon need
to address this problem.

Storing present-day paraffin blocks, with their bulky plastic mounts
and low-melting waxes, is going to become even more difficult than it
is now, as hospitals and other facilities consider the cost of
maintaining and cooling storage space.

I don't think it's possible to triage blocks and slides for disposal
at the time the case is signed out. It sounds like a good idea, but
the few times I've seen it tried it didn't work. Also, we really don't
know what we're going to need to recover in the future.

Bob Richmond
Samurai Pathologist (nearly 70, isn't going to have to worry about this problem)
Knoxville TN

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