Urine analyzer is an automatic instrument for determining some chemical components in urine. It is an important tool for automatic urine examination in medical laboratory. It has the advantages of simple and fast operation. Under the control of computer, the instrument collects and analyzes the color information of various reagent blocks on the test strip, and outputs the content of chemical components in urine after a series of signal conversion.
Urine analyzer is generally composed of test strip, mechanical system, optical system, circuit system, input and output system, etc. What is the important role of each part?
1. test strip
There are several reagent pads containing various reagents on the test strip, which can show different colors after independent reaction with the corresponding components in urine. The color depth is proportional to the components to be tested in urine. Different types of urine chemical analyzers have developed matching test strips suitable for their own use. The test strip adopts multilayer structure:
The first layer of nylon film plays a protective role to prevent macromolecular substances from polluting the reaction and ensure the integrity of the test strip;
The second cashmere layer, which includes the periodate area (some reagent modules contain this area) and the reagent area. The periodate area can destroy the interfering substances of vitamin C. the reagent area contains reagent components, which are mainly chemically changed with the components to be tested in urine, resulting in color changes;
The third layer is a water absorbing layer, which can make the urine infiltrate evenly and quickly, and inhibit the urine from flowing to the adjacent reaction zone;
The last layer of plastic sheet is used as the support).
Each reagent block reacts with the measured components in urine to show different colors. Generally, the reagent block to be tested is one more blank block than the analyzer test item. To eliminate the test error caused by the uneven distribution of urine color and reagent blocks, and improve the measurement accuracy.
2. mechanical system
The main function of the mechanical system is to transfer the test strips and samples to be tested to the testing area, and then discharge the test strips to the waste box after testing by the analyzer. Different types of instruments adopt different mechanical devices, such as gear combination, transmission belt, mechanical arm, sample aspirating needle, sample mixer, etc.
3. optical system
Optical system generally includes light source, monochrome processor and photoelectric conversion. The light irradiates the reactant surface to produce reflected light, and the intensity of the reflected light is proportional to the reaction color of each item. The reflected light of different intensity is converted into electrical signal by photoelectric converter and sent to amplifier for processing.
There are usually three kinds of optical systems for urine analyzer: light-emitting diode (LED) system, filter beam splitting system and charge coupled device (CCD) system.
4. circuit system
The circuit system amplifies the converted electrical signal, sends it to the central processing unit (CPU) for processing after analog-to-digital conversion, calculates the final detection result, and then outputs the result to the screen for display and to the printer for printing. The function of CPU is not only responsible for the processing of detection data, but also to control the organic operation of the entire mechanical system and optical system, and to realize multiple functions through software.
5. input / output system
It is composed of display, panel, printer and other components. It is used for the operator to input the specimen information, observe the working state of the instrument, print the report, etc.