Are you familiar with the methods and items of the hemagglutination apparatus?
Optical hemagglutinometer is based on the change of plasma turbidity during coagulation to determine coagulation function. According to the different optical measurement principle of the instrument, it can be divided into scattering turbidimetric method and transmission turbidimetric method.
The scattering turbidimetry is based on the change of scattering light in the solidification process of the sample to be tested to determine the detection end point. In this method, the monochromatic light source of the detection channel is at a 90° Angle to the photodetector. When coagulation activator is added to the sample, the scattered light intensity of the sample gradually increases with the formation of fibrin clots in the sample. When the sample is completely solidified, the intensity of scattered light does not change. Usually, the starting point of solidification is 0%, the end point of solidification is 100%, and the solidification time is 50%. This optical change is picked up by a photodetector and converted into an electrical signal, which is amplified and transmitted to a monitor for processing to trace the solidification curve.
Transmission turbidimetry, is according to the sample under test in the process of solidification absorbance changes to determine the solidification end point, and the scattering turbidimetry different is the method of optical path is the same as the colorimetric method like in a straight line arrangement: light processed into parallel light from the light source, through the sample under test after exposure to the photocell into electrical signal, after amplification monitoring process. When the coagulation activator was added to the sample, the absorbance was very weak at the beginning, and gradually increased with the formation of fibrin clot in the reaction tube. When the clot was completely formed, the absorbance tended to be constant. The hemagglutinometer can automatically depict the curve of absorbance change and set the time corresponding to a certain point as the coagulation time.
The magnetic bead method is based on the change of plasma viscosity during coagulation to measure coagulation function. According to the different principle of magnetic bead motion measurement, it can be divided into photoelectric detection method and electromagnetic bead detection method.
Photoelectric detection method, the role of photodetector in magnetic bead method is different from that in optical method, it only measures the motion law of magnetic beads during plasma coagulation, and has nothing to do with the turbidity of plasma. A pair of electromagnets in the magnetic bead method are placed at both ends of the test cup, and they generate constant alternating magnetic field to make the magnetic beads swing in the test cup. A pair of photoelectric receiving devices are placed in the vertical direction of the magnetic bead swing, and the solidification end point is determined when the magnetic bead swing is attenuated to 50%.
Electromagnetic detection method can also be called double magnetic circuit magnetic bead method. One pair of magnetic circuits is used to attract the magnetic bead swing, and the other pair of magnetic circuits uses the electrical signal generated by the magnetic field line cutting during the magnetic bead swing to monitor the magnetic bead swing amplitude reading. When the magnetic bead swing amplitude decays to 50%, the solidification end point is determined.
