Leica Biosystems PELORIS_PELORIS II - Manual (Page 63)

Protocol Setup
Leica PELORIS™ User Manual Rev K © Leica Biosystems Melbourne Pty Ltd 2011 63
Carryover has three main components:

Reagent on retort walls and baskets

Reagent on cassettes, and on and infiltrated into tissue

Reagent on and infiltrated into small-tissue carriers (e.g. biopsy pads, biopsy cassettes, wraps
etc.).
The reagent management system automatically calculates the carryover on retort walls and
baskets, taking into account the retort fill level and drip time.
The carryover due to cassettes and tissue is calculated using the number of cassettes entered by
users at the start of each run (in some cases an average number of cassettes may be used, see
6.1.2 Reagent Management). The amount of carryover on a standard cassette is used in the
calculation. Drip time is also included.
The reagent management system calculates carryover from small-tissue carriers using the protocol
Carryover value you set.
Carryover values are on a scale from 0 to 100:

A setting of 0 indicates that there is no carryover due to small-tissue carriers like biopsy pads,
i.e. the run has only standard cassettes with no small-tissue carriers.

A setting of 100 indicates there is carryover equivalent to having all the tissues in a run using
biopsy pads (biopsy pads have the maximum carryover of all small-tissue carriers).
Because biopsy pads can have up to 10 times the carryover of standard cassettes it is important to
set a truly representative Carryover value in your protocols (as it is to accurately enter the number
of cassettes in each run). If you set too high a Carryover value the system calculates too rapid
degradation of reagents and requires you to replace them sooner than necessary. With too low a
setting the system calculates that reagents are more pure than they are. You will use reagents
beyond their optimal effectiveness resulting in poor processing quality.
Protocol carryover values are set by supervisors on the Edit protocol screen (the default value is
set on the Reagent management screen). Tap the Carryover button and enter a number
between 0 (no carryover from small-tissue carriers) and 100 (maximum carryover from small-tissue
carriers).
How to Calculate Carryover Values
Carryover is dependent on the types of cassettes and other small-tissue carriers used: e.g. biopsy
pads, paper or tissue inserts, mini cassettes, biopsy cassettes etc. It also depends on the proportion
of these in each run.
The carryover setting is a protocol property, so it must be set to the average carryover value for
runs that use the protocol.
The following table shows the carryover values that should be used for a range of cassettes and
pads etc. provided by Leica Microsystems. The values in the table apply when all the tissue in the