27
V2.3.0 OM-UNN valid from 15
th
April 2015
4
Results and Reports
4.1
Principle of Analysis
The analyzer reads absorbance of all the reaction well at 450nm and 630nm, then calculate the actual
absorbance using the following formula:
OD
smp
= OD
450
– OD
630
4.1.1
Qualitative Tests
4.1.1.1
Calibration
During the qualitative tests, the optical density (OD) of the calibrator for each lot should be carried out.
The code of calibrator has two parameters:
OD
cal0
：
the expected OD of the calibrator
TOD
cal
：
the tolerance deviation of OD
cal0
After analysis, the instrument calculates the optical density of the calibrator (OD
cal
) using the formula.
If OD
cal ,
is within the following criteria as listed below, the Calibration Curve is accepted and the OD
cal
is
stored.
OD
cal0
–TOD
cal
≤OD
cal
≤ OD
cal0
+TOD
cal
The Correction Factor, K
cal
(the ratio between OD
cal
and OD
cal0
) is also stored for re-calibrating the Calibration
Curve.
4.1.1.2
Interpretation of Results
Once the samples are processed, its optical density will be determined as followed:
OD
450
– OD
630
It compares the sample’s optic density OD
smp
with its corresponding optic density of the calibrator OD
cal,
and
three kinds of conclusions are determined as follows:
If OD
smp
<0.8×OD
cal
Negative
If 0.8×OD
cal
≤ OD
smp
≤ 1.2×OD
cal
Doubtful
If OD
smp
>1.2×OD
cal
Positive
The doubtful range is defined symmetrically with respect to ODcal (See Fig.4-1), and the limits in percentage
20% are determined in the method file.
