Leica Biosystems PELORIS_PELORIS II - Manual (Page 79)

Reagent Setup
Leica PELORIS™ User Manual Rev K © Leica Biosystems Melbourne Pty Ltd 2011 79
5.1.5 Tissue Marking
Some laboratories have traditionally added eosin (or other dyes) to formalin or alcohol during tissue
processing, to aid in the visualization of tissue during embedding. This practise is NOT
recommended for the Peloris tissue processor. The dyes can build up on the liquid level sensors and
compromise performance. If you need to mark tissue for embedding, Leica Microsystems
recommends you add the dye at the grossing stage.
In spite of this recommendation, eosin can be used on the Peloris if the customer feels there are
strong reasons for doing so, and due care is taken. If using eosin on the Peloris add the dye to the
fixative in preference to the alcohol. However, rapid turnaround times can mean that tissue is at the
grossing stage for only a short time, and fixation steps on the Peloris can also be short. So some
customers prefer to add eosin at the alcohol stage. This is also acceptable if due care is taken.
Recommended eosin concentrations for the different stages are given below. Testing was
conducted using Surgipath Alcoholic Eosin (1%) – catalog no. 3801600.
Preference 1 – At Grossing
Use 10 mL of 1% liquid eosin per liter of formalin.
You can vary the concentration to correspond with the length of the processing protocol, where
some dye will be lost. A disadvantage of staining at grossing is that specimens are not immersed in
dyed formalin for the same amount of time.
Preference 2 – In Fixative on Peloris
Use 50 mL of 1% liquid eosin per 5 L Peloris reagent bottle of formalin.
Preference 3 – In Alcohol on Peloris (Xylene)
Use 10 mL to 25 mL of 1% liquid eosin per 5 L Peloris reagent bottle of ethanol (there are eight
ethanol bottles in the recommended bottle configuration for xylene processing).
Specimens are immersed in the marking reagent for the same amount of time, giving consistent
staining. Protocols longer than two hours may cause overstaining – reduce the eosin concentration
as required.
Preference 3 – In Alcohol on Peloris (Xylene-free)
Use 250 mL of 1% liquid eosin per 5 L Peloris reagent bottle of 85% ethanol (there are three bottles
of 85% ethanol in the recommended bottle configuration for xylene-free processing).
Specimens are immersed in the marking reagent for the same amount of time, giving consistent
staining. Protocols longer than two hours may cause overstaining – reduce the eosin concentration
as required.
CAUTION
If adding eosin to reagents on the Peloris be sure to clean the retorts daily to avoid
buildup of dye on the liquid level sensors, which can compromise performance. See
Clean Retorts in 7.2 Daily Tasks.