Bio-Rad iMark Microplate Absorbance Reader - Manual (Page 18)

iMark Microplate Absorbance Reader Instruction Manual
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The result absorbance value of the formula calculation and the gray zone value that is entered by the user are
used for the cutoff.
The upper and lower cutoff values are:
Upper cutoff absorbance = Result of a Formula + ((Gray zone/100) * Result of a Formula)
Lower cutoff absorbance = Result of a Formula - ((Gray zone/100) * Result of a Formula)
The absorbance range of the upper and lower cutoff is divided into 10 equal partitions, numbered 0 through 9.
The absorbance value of each well is classified according to the partition of the matrix to which it
corresponds and is reported as a signal digit. Wells with absorbance values greater than the upper cutoff are
reported by plus signs (+), and wells with absorbance values less than the lower cutoff by minus signs (-).
d. Ratio
The mean absorbance value of the Calibrator wells defined in the plate map and the concentration value
entered by the user are used for the cutoff ratio. Before the cutoff, the absorbance value of each well is
converted into the concentration value. The ratio of Concentration/Absorbance of Calibrator is applied to
the conversion. Then, the cutoff is done with the defined Positive and Negative or the defined Positive and
Gray zone values.
6. Curve Fit Report
The Curve fit report provides a regression analysis based on the absorbance values of a series of standards. There
are ten types of curve fits supported with the onboard software on iMark Microplate readers:
i. 5P Logistic Rodbard
ii. 4P Logistic Rodbard
iii. 5P Logistic Cook-Wilkenson
iv. 4P Logistic Cook-Wilkenson
v. 5P
Exponential
vi. Sigmoid Logistic
vii. Linear regression
viii. Quadratic regression
ix. Cubic
x. Point-To-Point
regression
The onboard software calculates the best fit of the defined curve between each set of two consecutive data points
in the standard curve of absorbance vs. concentration. And then it generates the report with the coefficients of
regression, the correlation coefficient, and the standard error.
For readers with the optional internal printer or with an external ESC/P printer which accepts ESC/P code, a
graph of the standard curve may be generated when selected in the report parameter.
7. Concentration Report
In case of the curve fit, the Concentration report also provides the regression analysis. After the calculation of the
curve fit, it calculates the concentrations values of the samples, and generates the report.
In case of the cutoff constant with the unit not designated "Abs" and in case of the cutoff ratio, the reader
generates the list of concentration of each well.
8. Difference Report
The Difference report is the subtraction report between the neighboring columns or row.