Point-of-care bacteria detection system—integrating a bacteria test strip and a color analysis application

Background: Infectious diseases are difficult to detect and cause a significant proportion of the healthcare burden. In undeveloped or developing countries, Infectious diseases can cause serious problems. Rapid quantification of bacteria is critical for healthcare. Methods: This research focused on the development of a colorimetric bacteria test strip suitable for detecting bacteria concentration in a liquid sample. We combined 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and phenazine methosulfate (PMS) to develop our MTT-PMS bacteria test strip for bacteria detection. The color changed from light green-yellow to purple based on the bacteria detection associated with the concentration. Results: Because a subtle difference in color was difficult to distinguish with the naked eyes, we developed a smartphone application (APP) capable of reading and interpreting the test strip RGB results as values equivalent to bacterial concentrations. We used equations for color analysis to remove the influence of environmental errors on detection, and then converted RGB value into grayscale. Conclusions: The result showed that a rapid point-of-care detection tool has been used to provide valuable bacteria information in only 15–20 minutes, potentially bringing great help for the healthcare issues.