[Histonet] B-5 Fixative

Bob Richmond rsrichmond at gmail.com
Sun Jul 31 16:43:20 CDT 2016

Jillian A. Russell, HT (ASCP)CM, QIHCCM, Supervisor, CDx Histology
Operations, R&D at Dako in Carpinteria CA asks:

>>I am wondering how many labs are using B-5 fixatives and how many are
using B-5 alternatives due to the mercury issue? - For those who have
switched to an alternative, have you noticed many differences from the
traditional B-5 fixative?<<

This is a very controversial topic. B-5 fixative contains a large quantity
of mercuric chloride, along with formaldehyde, and you really can't use it
any more. I gave up B-5 and Zenker's fixatives very reluctantly.

My personal opinion is that B-5 substitutes are no improvement on neutral
buffered formalin, and may compromise immunostains (which often specify NBF

Bob Richmond
Samurai Pathologist
Maryville TN

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