Research progress on color determination methods of reagent strips in routine urinalysis

Clinically, routine urinalysis includes more than 10 items, such as urine protein, urinary pH, urinary bilirubin and so on. The above items are usually analyzed by dry chemical methods. The principle is that after the urine infiltrates the reagent strips, the color changes can be observed in each strip. The color depth is related to the component concentration, and the darker the color, the greater the measured component concentration, and vice versa. In this paper, four color discrimination methods in urinary dry chemical analysis were introduced, i.e. the method based on integrating sphere photoelectric conversion, the method based on charge-coupled device (CCD) image sensor, the method based on color sensor, and the method based on the combination of color sensor and fiber bundle. Besides, the four methods were compared and analyzed. Finally, the recent research progress in urinalysis was reviewed. Key words: Urine; Dry chemical method; Color; Urine reagent strip