Urinalysis for diaper-wearing elderly people using a combination of cotton-based diagnostic devices and smartphone-based image analysis

Wei-Hsuan Sung, Chao-Min Cheng


Background: Urinary tract infection (UTI) is one of the most common bacterial infections, annually affecting 150 million people worldwide. The highest prevalence of UTI in the overall elderly population. However, practical problems have occurred in urine sampling in diaper-wearing elderly people. Our aim is to develop a new type of the in-vitro diagnostic devices based on “cotton”, which allows us to detect the nitrite concentrations in urine (i.e., biomarker for urinary tract infection). The combination of cotton-based diagnostic device and a smartphone-based image analysis would help the healthcare people early diagnose urinalysis-based diseases such as UTI, and improve the life quality in elderly populations around the world.
Methods: Our diagnostic device integrated into diaper is made up with three primary parts: a test pad, a flow channel made by hydrophobic and hydrophilic cotton and plastic packaging substrates. The smartphone-based image analysis (a specific APP) solved recording issues including variances in either light or focal distance. The mean value was calculated and analyzed based on 8-bit grayscale using ImageJ software and defined as 255– [experiment zone intensity].
Results: The nitrite test color changes from colorless to purple, correlating positively to concentration (from 0.156 to 5 µM) in both test paper only and test pad integrated with diaper and the mean value is calculated and analyzed.
Conclusions: Since this device is inexpensive, portable, simple, structurally integrating with diapers and functionally integrated with the smartphone-based application, it would have a wild range potential of becoming a commercially viable diagnostic system, in particular, for the daily healthcare of elderly people.