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cubated for a specified amount of time. The immunology reagent is then
dispensed into the sample, which creates optical turbidity by the antibo-
dy-antigen binding complex. This changes the light intensity at a certain
wavelength, and such change is proportional to the concentration of the
reaction mixture.
Following the preparation of the sample and the reagent, the optical
density (OD) is measured. After a few minutes have elapsed, a second
measurement takes place, after which the two ODs measured are com-
pared in terms of light intensity change, the value of which is given in
ΔOD.
Turbidimetric Test Result Calculation:
Concentration
The concentration value (µg FEU/ml) is calculated
from the change of light intensity (ΔOD). The software
of the instrument places a calibration curve on the
input function points, and based on the curve,
unknown concentration values can be determined
from the measured light intensity change. The
calibration curve points may be provided by the
manufacturer of the reagent. If such points are
absent, they have to be determined from a dilution
series by the user.
5.1.3 Chromogenic Measurement
The instrument has a specific function for measuring AT III and Protein
C and Plasminogen. For this purpose, the instrument is equipped with
measuring positions that contain 1 photometer unit that operates at a 405
nm wavelength.
During chromogenic measurements a sample of a specific volume is in
-
cubated for a specified amount of time. The reagent substrate is then
dispensed into the sample, which alters its optical quality, as can be seen
in its light intensity at a certain wavelength. The transmitted light intensity
change is proportional to the relative concentration of the reaction mixt-
ure.
Following the preparation of the sample and the reagent, the optical