Is automatic immunofluorescence analyzer a medical device?

Hello, Fully Automated Immunofluorescence Analyzer is an instrument based on the technology of immunofluorescence analysis, which is a Class II medical device under the regulations of China. Immunofluorescence analysis as a kind of immunoassay, FIA also exists in two modes, i.e. competitive and sandwich. The principle of measurement of the competition type (the competition type with labeled antigen, for example) is based on the immunoassay in which unlabeled antigen (Ag) and labeled antigen (Ag-L) compete to bind a limited number of antibodies (Ab). In the assay, the concentrations of Ab and Ag-L are fixed. When unlabeled Ag is added to the immunization mixture of Ab and Ag-L, the binding of Ag and Ab decreases the amount of Ag-L in immunocomplex with Ab. The more Ag is present in the sample, the less Ag-L is bound to Ab. From the decrease in the Ab-Ag-L immune complex or the increase in free Ag-L, the amount of antigen to be measured in the sample can be quantified. The reaction process is as follows: Ag+Ag-L+Ab≒(Ag:Ab)+(Ag-L:Ab) For sandwich immunoassay, the reaction principle is to immobilize an excessive amount of Ab on the immunoassay carrier, and then add a certain amount of Ag, and after the immunoassay reaction, add an excessive amount of labeled antibody (Ab-L), in order to form a "sandwich". "The more Ag is present in the sample, the better the immunocomplex will be. The more Ag is present in the sample, the more Ab-L is bound, and the stronger the labeled fluorescent signal of the sandwich immune complex. The reaction process is as follows: Ab+Ag≒Ab:Ag≒Ab:Ag:Ab-L.