Smartphone-Based Point-of-Care Urinalysis Under Variable Illumination

Area of Science:

• Clinical Chemistry
• Medical Diagnostics
• Biomedical Engineering

Background:

• Traditional urinalysis relies on color comparison with reference sheets, which are prone to visual errors and difficult to interpret.
• Subtle color differences on reagent pads are challenging to distinguish, especially with spatially separated color swatches.

Purpose of the Study:

• To develop an improved reference array arrangement for urine test strips to enhance visual accuracy.
• To propose a smartphone-based algorithm for automated urinalysis interpretation.

Main Methods:

• A new doughnut chart arrangement for reference color swatches was designed, surrounding each reagent pad on the strip.
• A colorimetric detection algorithm was developed to evaluate captured images of the test strip under various color spaces.
• The system was tested for ten different urine tests under diverse environmental illumination conditions.

Main Results:

• The new strip design allows for naked-eye evaluation without an additional reference sheet.
• The smartphone application provides accurate, on-the-spot diagnostic results.
• The proposed system demonstrated accurate performance without calibration requirements, suitable for real-life applications.

Conclusions:

• The redesigned urine test strip and smartphone application offer a user-friendly and accurate method for urinalysis.
• This innovation addresses the limitations of traditional visual interpretation, reducing errors and improving accessibility.