The working principle of dry fluorescence immunoassay analyzer:
The test substance in the sample and the fluorescently labeled antibody form an immune complex, and after a chromatographic process, they are solidified in the detection area and the quality control area respectively; when the reagent card reaches the detection area, the excitation light source of the analyzer emits light waves to the reagent card In the detection area and the quality control area, the solidified fluorescent immune antigen-antibody complex is excited, and the light waves emitted by the fluorescent substance are collected by the signal acquisition board and converted into electrical signals. The strength of the electrical signals is closely related to the concentration and number of fluorescent molecules. According to the strength of the feedback electrical signal, the concentration of the analyte in the sample to be tested is calculated.
As a kind of immunoassay, FIA also has two modes, namely competition type and sandwich type. Among them, the competitive type (take the labeled antigen competitive type as an example) is based on the immunoassay method based on the competition between the unlabeled antigen (Ag) and the labeled antigen (Ag-L) to bind to the limited antibody (Ab). During detection, the concentration of Ab and Ag-L is fixed. When unlabeled Ag is added to the immune mixture of Ab and Ag-L, the combination of Ag and Ab reduces the amount of the immune complex between Ag-L and Ab. The more Ag present in the sample, the less Ag-L binding Ab-Ag-L. From the decrease of Ab-Ag-L immune complex or the increase of free Ag-L, the content of the antigen to be tested in the sample can be quantitatively determined. The reaction process is as follows: Ag+Ag-L+Ab≒(Ag:Ab)+(Ag-L:Ab)
The dry fluorescence immunoassay analyzer is generally composed of an optical unit, a mechanical unit, a control unit, and an output/display unit. The control unit controls the optical unit and the mechanical unit, and the output/display unit outputs the test results. Among them, the optical unit is the key module of the analyzer, and generally uses LED blue light or diode laser. At present, there are two types of dry fluorescence immunoassay analyzers on the market. One is a fully automatic analyzer with automatic sample addition function; the other is a "portable", which requires manual sample addition on the matching reagent card. Put it on the analyzer for testing. The fully automatic analyzer has advantages in processing large quantities of clinical and physical examination samples, and has the advantages of simplicity, efficiency, and speed; the "portable" analyzer is suitable for bedside and grassroots community hospitals. It has the advantages of small size, instant, convenience, and acceptance Environmental factors have little influence.
Fluorescence immunoassay technology has the advantages of strong specificity, high sensitivity, and good practicability. Therefore, it is used to measure low-content biologically active compounds, such as proteins (enzymes, receptors, antibodies), hormones (steroids, Thyroid hormones, phthalate hormones), drugs and microorganisms, etc.
