Stat Fax 303 Plus, Operator'S Manual

Page: 21 / 52

Awareness Technology, Inc. Stat Fax 303 Plus Operator’s Manual Rev. J 17
2.1.2 Selecting a Mode
This instrument contains several pre-programmed general purpose calculations which have been
selected to facilitate data handling for enzyme immunoassays and other similar tests.
1. Absorbance Mode (ABS key)
2. Calibrator (Single Standard) Mode (STND key)
3. Cutoff Mode (CUT key)
4. Multi Standard Mode (MULT key) - includes Regression Mode and point-to-point calculation.
5. % Absorbance Multi-Point Mode (%ABS key)
6. Uptake Mode (UPT key)
7. Alternately, a previously-stored test could be recalled from your user test menu at this time.
(Instructions for that are found in section 2.3, User Test Menu) (MENU key)
The mode designations are located above the first 6 numbered keys on the keypad. When any
of these is selected, the printer will print the date, the time, and the name of the mode selected,
and the display will indicate the next instruction.
A brief description of each mode follows. For a more detailed description, see section 2.2.
In the Absorbance Mode , the Microstrip Reader reads and prints the absorbances at the user-
selected wavelengths. Blanking is optional.
In the Calibrator (Single Standard) Mode , the instrument first accepts a calibrator singly or in
duplicate, then calculates concentrations based on a single-point standard curve passing
through the point (0,0). A blank is required in the first well (or first two wells if duplicate blank is
selected). A factor (equal to the concentration of the calibrator ÷ the absorbance of the calibrator)
is generated in this mode and then multiplied by subsequent absorbances to determine
concentrations. Duplicates, cutoff interpretation, and control options are available.
In the Cutoff Mode , a number of negative controls are read, followed by a number of positive
controls. Blanking on the first well is optional. The instrument calculates the mean of the
positives and the mean of the negatives. It also checks the individual control wells or the means
for QC purposes. It adds three terms: one user-entered number “X” multiplied by the mean of the
negative controls, another user-entered number “Y” multiplied by the mean of the positive
controls, and a third user-entered number “Fac”. The user may also select an equivocal range.
This determines cutoff points for interpretation of subsequent specimens.
In the Cutoff Control Mode , negative controls, cutoff controls, and positive controls may be read
in any combination. Blanking on the first well is optional. The instrument calculates a cutoff value
from the mean of cutoff controls. It also checks the individual control wells or the means for QC
purposes. The user may select Correction factor and equivocal range options. These adjust the
cutoff value to determine cutoff points for interpretation of subsequent specimens.