Classification of In Vitro Diagnostic Reagents Based on Detection Principles

According to the detection principles or methods, ivd in vitro diagnostics can be divided into biochemical diagnostic reagents, immunodiagnostic reagents, molecular diagnostic reagents, microbiological diagnostic reagents, urine diagnostic reagents, coagulation diagnostic reagents, hematology and flow cytometry diagnostic reagents, etc. Biochemical, immunological and molecular diagnosis reagents are the three main types of diagnostic reagents in China, and nucleic acid diagnosis in molecular diagnosis currently occupies the main market. Biochips are an important trend for future development, but currently, due to high costs, development difficulties, and relatively small usage, their use is still limited.

Ivd in vitro diagnostics: biochemical diagnostics

Biochemical testing started early and, at the same time, because of its advantages of low cost and fast speed, even with the vigorous development of diagnostic technologies such as immunodiagnostics and molecular-diagnostics, it still maintains a large market share. It is expected that biochemical diagnosis will still be an important diagnostic method for a considerable period of time in the future.

If viewed from the perspective of the testing end, the detection principle of biochemical diagnostic testing projects is basically the same. It mainly uses specific substrates or products of specific biochemical reactions of certain substances, and then quantitatively detects the concentration of the target substance through a detection instrument--such as a spectrophotometer--to infer whether the content of certain biochemical substances in the human body, such as sugar, fat, and protein, is within the normal range.

Ivd in vitro diagnostics: immunological testing

Immunological testing is one of the largest, fastest-growing diagnostic-method fields with the most new additions in the ivd in vitro diagnosis field. In principle, immunodiagnostics use the specific binding of antigens and antibodies. However, there are many methods at the testing end, and various testing methods are used, such as radioimmunoassay (RIA), colloidal gold technology that uses chloroauric acid for binding with protein polymers under particular conditions, enzyme-linked immunosorbent assay (ELISA) that uses an active enzyme as a label molecule, time-resolved fluoroimmunoassay (TRFIA) that uses long-lived fluorescence characteristics of lanthanide elements in chelating complexes for specific detection, and chemiluminescence immunoassay (CLIA), which combines the principles of chemiluminescence and immunoreaction.

RIA causes greater environmental pollution and is gradually being replaced by other immunodiagnostic methods. Currently, ELISA is a more mainstream method in immunodiagnostics.

Ivd in vitro diagnostics: molecular diagnostics

Nucleic acid diagnosis is the main part of molecular diagnosis currently, and the other part is biochip technology. The detection target of molecular diagnosis directly determines genetic material and expression forms that determine the characteristics of life, including DNA, RNA, and proteins. In terms of specific diagnostic technologies, the representational technology in nucleic acid diagnosis is polymerase chain reaction (PCR), and there are also DNA sequencing, fluorescence in situ hybridization (FISH), DNA blotting, single-nucleotide polymorphism (SNP), and ligase chain reaction (LCR). Biochips include gene chips and protein chips. PCR is currently the main method used in in vitro diagnostics for nucleic acid testing.