B-5 Fixative, Mercuric-Chloride

Description

PURPOSE: B-5 fixative is routinely used for bone marrow biopsies, and on some
lymph nodes when lymphomas are suspected.

REAGENTS:
Stock B-5 Solution:
Mercuric chloride 12.0 gm
Sodium acetate 2.5 gm
Distilled water 200.0 ml
Mix well, do not use any metal
utensils or foil lined lids,
solution is stable for 1 year.
Initial and date.
Working Solution:
Stock solution 20.0 ml
Formaldehyde 2.0 ml
Mix immediately before use.
Discard solution according to the
hazardous waste regulations.
CAUTION: CARCINOGENIC, IRRITANT,
CORROSIVE
SAFETY: Work in well ventilated area, wear gloves, lab coat, and goggles.
Mercuric chloride; severe skin and eye irritant. Target organ effects on
reproductive, urogenital, respiratory, gastrointestinal and fetal systems via
ingestion and inhalation routes. Corrosive to metals.
Formaldehyde: severe eye and skin irritant. Sensitizer by skin and respiratory
contact. Toxic by ingestion and inhalation. Target organ effects on
respiratory system. Corrosive. Carcinogen.
DISPOSAL: Pour used B-5 fixative in a glass bottle labeled as “B-5 Waste”, do
not pour down the drain. Follow instructions for WASTE REDUCTION in the
Histology SOP Manual. To be disposed of by Safety Services.
FIXATION TIME: 2 to 4 hours, note time on container, do not leave overnight.
PROCEDURE:
1. Retain fixed specimen in 10% formalin or 70% alcohol.
2. Tissue sections that are B-5 fixed contain mercury deposits and must be
treated to remove the pigments prior to staining, after deparaffinizing:
a) Lugol’s iodine: 5 minutes, wash.
b) 5% hypo: 5 minutes, wash and stain as desired.
REFERENCE: Sheehan,D and Hrapchak,B: Theory and practice of Histotechnology, 2nd Ed., 1980,
pp. 42-43, 46-47, Battelle Press, Ohio
Crookham,J, Dapson,R, Hazardous Chemicals in the Histopathology Laboratory, 2nd ED, 1991, Anatech