Carry-Over Evasion Function; Method Of Carry-Over Evasion; Condition For Carry-Over Evasion; Carry-Over Evasion-Specified Pattern - Hitachi 902 Service Manual

3.5

Carry-over Evasion Function

(1) Outline
The carry-over evasion function is provided to prevent occurrence of inaccurate data due
to sample carry-over in photometry assay and ISE tests.
This function works on routine samples alone and does not work on calibrator and control
samples. Carry-over is evaded by changing the measuring sequence among the reagents
or samples, which may cause carry-over, or by execution of washing. The kinds of
evasion/washing are listed below.
(a) Evasion of reagent carry-over due to reagent probe and washing for evasion
(b) Evasion of carry-over between reagents due to cell and washing for evasion
(c) Evasion of sample carry-over due to sample probe and washing for evasion
(a) Evasion of reagent carry-over due to reagent probe and washing for evasion
(I)

Condition for carry-over evasion

When the evasion of reagent carry-over due to reagent probe is set, it is
attempted at first by changing the reagent sampling sequence (test sequence).
If this method is unusable, carry-over evasion by washing is executed. That is,
when the sequence of pipetting reagents (R1 to R3) with the reagent probe
matches the specified pattern, carry-over is prevented by (i) to (iii) below. In (ii)
and (iii), throughput is degraded.
(i)
(ii) When step (i) cannot be taken, a channel is registered after reagent probe
(iii) Cell is made blank and the system waits till deviation from the specified
(II)

Method of carry-over evasion

The reagent probe is washed by aspirating detergent (detergent 1 or 2) or
system water (distilled water for washing the inside of probe) and discharging it
into a cell. At this time, the stirring rod is also washed in that cell.
(III)

Carry-over evasion-specified pattern

The patterns, for which the evasion of carry-over between reagent types is
specified, are listed below.
"→ ALL" indicates that evasion is required in all types of R1, R2 and R3.
ALL represents 3 reagent types for 3-reagent system, and 2 reagent types for 2-
reagent system.
(IV) Registration of carry-over evasion-specified pattern
Up to 40 kinds of patterns, for which the evasion of carry-over due to the
reagent probe is specified, can be registered.
For avoiding the relevant pattern, channel registration is changed for a
different test within the test sequence of the same sample.
washing cycle.
pattern.
R3 → R3, R3 → R2, R3 → R1,
R2 → R3, R2 → R2, R2 → R1,
R1 → R3, R1 → R2, R1 → R1
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