Stanford engineers design a home urine test that could scan for diseases

Invented to test blood sugar in 1956, the standard dipstick test is now a paper strip with 10 square pads. Dipped in a sample, each pad changes color to screen for the presence of a different disease-indicating chemical. After waiting the appropriate amount of time, a medical professional – or, increasingly, an automated system – compares the pad shades to a color reference chart for results.

Considering the dipstick as a given, Bowden and Smith, the engineers, designed a system to overcome three main potential errors in a home test: lighting, volume control and timing.


As a color-based test, the dipstick needs consistent lighting conditions. The same color can look different depending on its background, so the engineers created a black box that covers the dipstick. Its flat, interlocking parts make it easy to mail, store and assemble. They also tackled volume control.

To fix this, the engineers designed a multi-layered system to load urine onto the dipstick. A dropper squeezes urine into a hole in the first layer, filling up a channel in the second layer and ten square holes in the third layer. When the third layer is inserted into the black box, some clever engineering ensures that a uniform volume of urine is deposited on each of the ten pads on the dipstick at just the right time.

Finally, a smartphone is placed on top of the black box with the video camera focused on the dipstick inside the box. Custom software reads video from the smartphone and controls the timing and color analysis.

To perform the test a person would load the urine and then push the third layer into the box. When the third layer hits the back of the box, it signals the phone to begin the video recording at the precise moment when the urine is deposited on the pads.

Timing is critical to the analysis. Pads have readout times ranging from 30 seconds to 2 minutes. Once the two minutes are up, the person can transfer the recording to a software program on their computer. For each pad, it pulls out the frames from the correct time and reads out the results.

Detailed coverage can be found from Stanford website following this link.