Study on a novel core module based on optical fiber bundles for urine dry-chemistry analysis

Abstract

A core module with a novel optical structure is presented to analyze urine by the dry-chemistry method in this paper. It consists of a 32-bit microprocessor, optical fiber bundles, a high precision color sensor and a temperature sensor. The optical fiber bundles are adopted to control the spread path of light and reduce the influence of ambient light and the distance between the strip and sensor effectively. And the temperature sensor is applied to detect the environmental temperature to calibrate the measurement results. Therefore, all these can bring a lot of benefits to the core module, such as improving its test accuracy, reducing its volume and cost, and simplifying its assembly. Additionally, some parameters, including the calculation coefficient about reflectivity of each item, semi-quantitative intervals, the number of test items, may be modified by corresponding instructions in order to enhance its applicability. Meanwhile, its outputs can be chosen among the original data, normalized color values, reflectivity, and the semi-quantitative level of each test item by available instructions. Our results show that the module has high measurement accuracy of more than 95%, good stability, reliability, and consistency and can be easily used in various types of urine analyzers.

A portable analyzer based on a novel optical structure for urine dry-chemistry analysis

“…In the analyzer, both color sensor A and color sensor B are S9032-02, a kind of highperformance color sensor with three-channel photodiodes sensitive to red, green and blue (RGB) regions of the light spectrum respectively. And the sensitive peak wavelengths of this type sensor are 620 nm, 540 nm, 460 nm with relatively narrow three intervals of wavelengths [6].…”

“…However, among them, the semi-quantitative urinalysis, a urine dry-chemistry detection way, is a widely recognized method of the common test in clinical assay and has been determined as a basic program for physical examination because it is very meaningful, cheap and convenient [5]. The fundamental principle of urine semi-quantitative analysis is that both some characteristics of urine and the quantity of some chemical composition in urine are closely relative with color changes of urinalysis reagent piece (URP), produced by some specific chemical reactions [6]. In practice, a URP corresponds to a defined test item of human urine, such as protein, nitrite, glucose, vitamin C. For the convenience of testing, some urinalysis reagent pieces (URPs) about different test items are usually fixed on a urinalysis reagent strip (URS).…”

“…The way mainly depends on the adopted optical structure and the type of photoelectric sensor. As far as it goes, there are three basic methods to be reported by some researchers [6,9] and to be used in the commercial urine analyzers. In the first method, the color value of each URP is gained by using the photodiode or photoelectric triode to detect the reflected-light intensity while the several different-wavelength lights illuminate the URP from different angles in turn.…”

“…All these result in a higher cost and more complex optical construction than the other two methods. As a consequence, in fact, the third way is usually applied in the large fully automatic urine analyzers, while the other two ways are often taken in the portable urine analyzers [6].…”

“…Additionally, the measuring accuracy of the urine analyzers are also closely related to the algorithm, the ambient light, environmental temperature, URS itself and so on. In our previous study [6], we have presented an core module of urine analysis with a novel optical structure that can effectively reduce the influence of stray light and environmental temperature. However, it can't realize the automatic adjustment of light intensity, and can't directly monitor light intensity during the whole testing.…”