Working principle
Different types of coagulation instruments use different principles. At present, the main detection methods are the coagulation method, substrate chromogenic method, immune method, latex agglutination method, etc.
1. Coagulation method (biophysical method)
The coagulation method is to detect the changes of a series of physical quantities (light, electricity, mechanical motion, etc.) in plasma under the action of a coagulation activator, and then analyze the obtained data by computer and convert it into the final result, so it can also be called biological physical law.
2. Substrate chromogenic method (biochemical method)
The substrate chromogenic method is to infer the content and activity of the tested substance by measuring the absorbance change of the chromogenic substrate, which can also be called the biochemical method. The principle is to artificially synthesize a small peptide that has a similar sequence of amino acids to natural coagulation factors and contains a specific action site and connects the chemical gene that can be hydrolyzed to produce color with the amino acid of the active site. During the determination, because the coagulation factor has the activity of the proteolytic enzyme, it can not only act on the natural protein peptide chain but also act on the synthetic peptide chain substrate, thereby releasing the chromogenic gene and making the solution color. The shade of color produced is proportional to the activity of the coagulation factor, allowing accurate quantification. At present, there are dozens of synthetic peptide substrates, and the most commonly used is p-nitroaniline (PNA), which is yellow and can be measured at a wavelength of 405 mm.
3. Immunological methods
In the immunological method, the purified test substance is used as the antigen, and the corresponding antibody is prepared, and then the test substance is qualitatively and quantitatively determined by the antigen-antibody reaction.
Development History
In 1910, Kottman invented the world's earliest coagulation instrument, which reflects the time of plasma coagulation by measuring the change of viscosity during blood coagulation.
In 1922, Kugelmass used a turbidimeter to measure the change in transmitted light to reflect the plasma coagulation time.
In 1950, Schnitger and Gross invented a coagulation apparatus based on the electro-galvanic method.
In the 1960s, mechanical coagulation instruments were developed, and the early planar magnetic bead method appeared.
After the 1970s, due to the development of the mechanical and electronic industries, various types of automatic coagulation instruments have come out successively.
In the 1980s, due to the emergence of chromogenic substrates and their application in the detection of blood coagulation, the automatic coagulation instrument can not only perform general screening tests, but also detect single factors of coagulation, anticoagulation, and fibrinolysis systems. The detection of anticoagulation and fibrinolysis becomes possible.
In the late 1980s, the invention of the dual magnetic circuit magnetic bead method brought a new concept to the detection of thrombus and hemostasis. Due to its unique design principle, some influencing factors of optical detection no longer exist in this type of detection instrument.
In the 1990s, the development of the immune channel of the automatic coagulation instrument integrated various detection methods, and the detection items were more comprehensive, which provided a new method for the detection of thrombus and hemostasis.