Milestone s.r.l.
MM098-002
– LOGOS ONE – Operator Manual
118
A. Appendix
A.1. TISSUE PROCESSING THROUBLESHOOTING GUIDE
PROBLEM
BLOCK/SLIDE
POSSIBLE CAUSES
RIMEDIAL ACTION
Pyknotic nuclei and
severe
cytoplasmic
distortion of the tissue
section.
Poor dehydration.
Tissue sections have the
microscopic appearance of
pyknotic nuclei and severe
cytoplasmic
distortion
(overheated appearance).
Opaque
white
surface
appearance and softness of
some areas of the block after
the trimming.
1.
Tissue has been poorly fixed and
processed
exclusively
with
JFC
solution (JFC is NOT a fixative).
2.
Water contamination of heated ethanol
step due to carry over of water from
rinsing alcohols or the quality of
ethanol in use is less than 100% (poor
dehydration).
3.
Water carry over is increased in rinsing
alcohols by the use of sponge biopsy
pads (poor dehydration).
4.
For small biopsy samples: inadequate
dehydration due to use of paper wraps
that restricts the flow of reagents.
For larger biopsies: processing time
selected is inadequate for dehydration.
5.
Additives used in some commercial
formalin fixative preparations interfere
with JFC, even though tissues are well
fixed in formalin (rare occurrence).
1.
Tissues to be fixed overnight in formalin, if
using JFC exclusively. Introduce an ethanol
step to post fix tissues with ethanol, prior to
using JFC.
OR
Use Ethanol-Isopropanol processing.
2.
Replace used ethanol with fresh 100%
ethanol (pure or reagent grade).
AND
Implement regular checks of ethanol with a
Hydrometer, to ensure that heated ethanol is
100% quality (water free).
3.
Introduce an extra (third) ethanol rinse to
ensure sponge pads are well cleansed.
4.
For small biopsies with biopsy wraps: do not
use the small biopsy run but instead increase
the processing time in the ethanol and
Isopropanol to compensate for the wraps
restricting reagent flow.
AND
For larger samples sizes: increase the
processing time.
5.
Introduce an ethanol step to wash out the
contaminants from the tissues, prior to using
JFC.