Hitachi 902 - Automatic Correction of Reaction Limit Level; Reaction Limit Level Check; Relationship between Alarm Name and Photometric Point

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(2) Reaction Limit Level Check
When concentration or enzyme activity is abnormally high in a rate assay test, correct
data is unobtainable because the substrate or coenzyme in reagent is consumed
completely. Therefore, the upper or lower reaction limit absorbance is set for check .
Check is made on the absorbance at the main wavelength alone.
< Relationship between Alarm Name and Photometric Point >
When 4 points or more over the specified photometric range are within the reaction limit,
measurement is carried out normally. In case no point, 1 point or 2 points are within the
reaction limit, a reference value is obtained depending on an absorbance change
between the first two points. In case 3 points are within the reaction limit (with comment
LIMT2), the value obtained depending on an absorbance change among the first three
points is printed as a reference value.
Input photometric range
(with comment LIMT0)
Input photometric range
(with comment LIMT1)
Input photometric range
(with comment LIMT2)
Input photometric range
(with comment LIMT2)
Reaction limit
level
ABS.
ABS.
ABS.
ABS.
Reaction limit level
Time
Time
Time
Time
Fig. 2-1 Reaction Limit Level Check
< Automatic Correction of Reaction Limit Level >
The instrument corrects the input reaction limit level by adding an absorbance value due
to sample turbidity, etc.
Reaction limit level = Input reaction limit absorbance value + (L
1
- L
B
)
L
1
: Sample absorbance at photometric point 1
L
B
: Reagent blank absorbance at photometric point 1
When L
1
- L
B
≤ 0, automatic calibration will not be performed.