Urine analyzer is an automated instrument for determining certain chemical components in urine. It is an important tool for automated urine inspection in medical laboratories. It has the advantages of simple and fast operation. Under the control of the computer, the instrument collects and analyzes the color information of various reagent blocks on the test strip, and undergoes a series of signal conversion, and finally outputs the measured chemical composition content in the urine.

1. The working principle of urine analyzer

（1）. Reagent strip structure:

The first layer of nylon membrane: plays a protective role to prevent contamination of the reaction by macromolecular substances.

Second layer of fleece layer: It includes iodate layer and reagent layer. The iodate layer can destroy interfering substances such as vitamin C, and the reagent layer contains reagent components, which mainly chemically react with the measured substances in the urine to produce color changes.

The third layer of water-absorbing layer: It can make the urine evenly and quickly immerse, and the YZ urine can flow to the adjacent reaction zone.

Fourth layer: a plastic sheet that is not infiltrated by urine as a support. The reaction principle and influencing factors of the reagent strip. Application of reagent strips Different types of urine analyzers generally use their own special reagent strips. In addition, one more blank block and one reference block.

（2）. Measuring principle:

After immersing the reagent strip in urine, except for the blank block, the other reagent blocks have a color change due to the chemical reaction with the urine. The color depth of the reagent block is proportional to the reflectance of light, and the color depth is proportional to the concentration of various components in the urine. As long as the reflectance of light is measured, the concentration of various components in urine can be obtained.

Urine analyzer is generally controlled by a microcomputer, and semi-quantitative determination is performed by measuring the color change on the reagent strip by using a spherical area spectrometer to receive dual-wavelength reflected light. The measured wavelength is the sensitive characteristic wavelength of the test agent block, and the other is the reference wavelength, the insensitive wavelength of the test agent block, which is used to eliminate the influence of background light and other stray light.

2.Structure of urine analyzer

Urine analysis technology is generally believed to have started in the 1950s, and its principle is reflected photoelectric colorimetry. Commonly used urine analyzer structures include mechanical systems, optical systems, circuit control systems, analysis and processing software, display and printing systems.

As shown in the figure below, when the test strip impregnated with urine sample is placed on the test strip holder, the transport mechanism of the urine analyzer will transfer the test strip to directly below the optical system, and the light source illuminates the test strip After each reagent block that has produced a chemical reaction, the reflected light is received by the photoelectric converter. Each reagent block in the test strip reacts independently with the corresponding components in the urine to display different colors. The depth of the color is directly proportional to the concentration of each biochemical component in the urine.

There is also a blank block in the test strip to compensate for errors caused by changes in urine color and urine analyzer. The detected light intensity of each reagent block and the reflected light of the blank block are converted into digital signals by the circuit system, and sent to the ZY processor (CPU) to calculate the reflectivity, thereby determining the biochemical components in the urine Content. The results can be displayed on the display or printed.

3. Classification of urine analyzers

(1) . Classification according to working methods: It can be divided into wet urine analyzer and dry urine analyzer. Among them, the dry urine analyzer is mainly used to automatically evaluate the measurement results of the dry test paper method. Because of its simple structure and convenient use, it is widely used in clinical practice.

(2) . Classified by test items: can be divided into 8 urine analyzers, 9 urine analyzers, 10 urine analyzers, 11 urine analyzers, 12 urine analyzers, 13 urine analyzers Instrument and 14 urine analyzers. Test items include urine protein, urine glucose, urine pH, urine ketone bodies, urine bilirubin, urobilinogen, urine occult blood, nitrite, urine white blood cells, urine specific gravity, vitamin C and turbidity.

(3) . According to the degree of automation: it can be divided into semi-automatic urine analyzer and automatic urine analyzer.

①Semi-automatic urine analyzer

At present, there are many manufacturers producing semi-automatic urine analyzers, which are simple in principle, small in size, low in cost and short in development cycle. It is easy to find substitutes for urine test strips, thus occupying a large number of domestic user markets.

The structure, interface and operation of the semi-automatic urine analyzer are relatively simple, but the samples need to be introduced one by one, and the specimens are mixed by hand. Generally, there is no automatic barcode scanning. The urine test strip needs to be directly immersed in the urine cup by hand, which may easily cause the color of a reagent pad area. Too deep, too much urine oozes and pollutes the adjacent reagent pad area, and it is easy to cause indirect pollution to the operator and the experimental bench.

②Automatic urine analyzer

Fully automatic urine analyzers generally use cleverly designed transmission devices, which have added functions such as automatic sample transfer, sample suction, sample spotting, cleaning, test strip feeding, and waste collection, which are suitable for the determination of batches of specimens, large hospitals or physical examinations. Units are used more. It has the advantages of fully automatic sample injection, automatic shaking of specimens, automatic scanning of test tube barcodes, reduction of manual numbering work, accurate grasp of the amount of sample spotting and sample spotting time, no pollution of adjacent reagent pads, and less pollution to the operator. Equipped with quality control liquid.