Components of urine analyzer

Urine analyzer is generally composed of test strip, mechanical system, optical system, circuit system, input and output system, etc.
1. Test strip
There are several reagent pads containing various reagents on the test strip, each of which can present different colors after independent reaction with the corresponding components in urine, and the depth of color 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 a multi-layer membrane structure: the first layer of nylon membrane plays a protective role, preventing the contamination of macromolecular substances to the reaction and ensuring the integrity of the test strip; the second layer of velvet 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 mainly undergo chemical changes with the components to be tested in urine to produce color changes; the third layer is a water-absorbing layer, which allows urine to penetrate evenly and quickly, and can inhibit urine from flowing to adjacent reaction areas; the last layer of plastic sheet is used as a support). Each reagent block reacts with the components to be tested in urine and presents different colors. Usually, the reagent block of the test strip has one more blank block than the test items of the analyzer. This is to eliminate the test errors caused by the color of the urine itself and the uneven distribution of the reagent blocks, and improve the measurement accuracy.
2. Mechanical system
The main function of the mechanical system is to transfer the test strip and the specimen to be tested to the test area, and the analyzer will discharge the test strip to the waste box after testing. Different types of instruments use different mechanical devices, such as gear combinations, transmission tapes, mechanical arms, sample suction needles, sample mixers, etc.
3. Optical system
The optical system generally includes three parts: light source, monochrome processor and photoelectric conversion. Light irradiates the surface of the reactant to produce reflected light, and the intensity of the reflected light is proportional to the reaction color of each item. Reflected light of different intensities is converted into electrical signals by the photoelectric converter and sent to the amplifier for processing.
There are usually three types of optical systems for urine analyzers: light emitting diode (LED) system, filter spectroscopic 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 test results, and then outputs the results to the screen for display and sends them to the printer for printing. The CPU is not only responsible for the processing of test data, but also controls the organic operation of the entire mechanical system and optical system, and realizes multiple functions through software.
5. Input and output system
It consists of components such as display, panel, printer, etc. It is used for operators to input specimen information, observe the working status of the instrument, print reports, etc.