24 Stat Fax 303 Plus Operator’s Manual Rev. J
Awareness Technology, Inc.
The instrument will read the strip and simultaneously display and print the results. A letter “B”
will appear beside the first well or wells to indicate blanking. The symbol “C1” will be printed
beside the calibrator well or wells, indicating that the well(s) contained calibrator material.
The display will then prompt “PLOT CURVE Y/N”. Press YES to print the curve. Press NO and
the display will prompt “Accept Curve Y/N”. Press YES if the curve is acceptable. Press NO
and the display will prompt “Re Start Y/N”. Press YES to recall the test, or NO to return to the
“Accept Curve Y/N” prompt.
2.2.3 Cutoff Mode
In the Cutoff Mode, X is multiplied by the mean of the negative controls, Y is multiplied by the
mean of the positive controls, and each of these two numbers are added to the FAC to obtain
the cutoff value.
For example, your package insert says that the cutoff value is .1 * the mean of the positive
controls + .02. You would enter 0 for X, .1 for Y, and .02 for FAC.
a.) To select this mode, press the CUT key. The display will then show “C/O Control Y/N”. If
you wish to use cutoff controls, press YES and go on to section 2.2.3-b; otherwise, when you
press NO the display will show “Cutoff Mode Y/N”. The cutoff mode uses the equation:
CO=X*mNC+Y*mPC+ Fac
where CO is the cutoff absorbance, mNC is the mean of the negative controls, and mPC is the
mean of the positive controls. X, Y, and FAC are user entered coefficients that can have any
positive or negative numerical value (including 0 and 1). Press YES. After the filters are
selected, if you chose no differential, the Offset Absorbance questions will follow (see section
2.4.5-Differential Absorbances for instructions).
The instrument will give you the choice for reverse cutoff. The display will show “POS IF > C/O
Y/N”. Press YES to choose the regular Cutoff Mode. If you press NO, the display will show
“POS IF < C/O Y/N”. Press YES to select the Reverse Cutoff Mode, in which absorbances lower
than the cutoff are labeled positive. Note that in the Reverse Cutoff Mode, negative controls
have high absorbances and positive controls have low absorbances. All relation signs (> and <)
are reversed in this mode. The regular Cutoff Mode is described below, followed by notes on the
Reverse Cutoff Mode. In addition, the “Blank” is not subtracted in the reverse cutoff option. The
following description is for the normal cutoff mode.
The instrument will then prompt “BLANK Y/N”. If you press yes, the instrument will display
“Blank <=?”. The reader will use this value to check that the blank is valid. Type the greatest
acceptable absorbance value for the blank material relative to air, and then press ENTER. The
blank absorbance will be subtracted from all subsequent wells, and will be flagged if it exceeds
the set limit.
The instrument now prompts for the X, Y and Factor values. Type each of these values followed
by the ENTER key. If Y=0 and Factor=0, the display will prompt “Min C/O Y/N”. Press YES if
your test has a minimum cutoff value. If X*mNC is less than the Min C/O, the Min C/O will be
used as the cutoff. The display will prompt “Min C/O =”. Enter the minimum cutoff value.
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