Low-Cost Sensor to Detect the Blood in Urine

The late detection of abnormalities in humans is one of the main problems that arise to face other pathologies. In this context, non-invasive techniques, such as urine tests, have currently become one of the most interesting tools. Especially, the urine tests are one of the easiest and accessible biological fluids, that provided relevant information. In this paper, we propose an optical sensor that is capable of detecting blood in urine in patients using a probe. This sensor is based on the use of different colour light sources (blue, green, yellow, orange, red, and infrared). Facing these light sources, we include a total of six light detectors to measure the absorbed light. In this experiment, 100 mL of urine from two volunteers were used as samples. Then, different volumes of blood have been added (0 mu L, 10 mu L, 25 mu L, 40 mu L, 55 mu L, 70 mu L) to generate six different cases where blood is present in the urine. The obtained voltage when the samples are analyzed showed that the minimum difference between the 0 mu L/L and 70 mu L/L is for the blue colour with 0.13 V and 0.14 V respectively. Otherwise, the maximum difference of voltage is found for the green wavelength with 0.18 and V 0.16 V. To conclude, it was decided to use a combination of green and blue colours to detect and quantify blood in the urine.