Washington: Scientists have designed a new low-cost urine test that uses a black box and smartphone camera to scan for multiple diseases from the comfort of your home.
A portable device allows patients to get consistently accurate urine test results at home, easing the workload on primary care physicians, researchers said. Audrey Bowden, assistant professor at Stanford University in the US and Gennifer Smith, a PhD student in electrical engineering, designed a system to overcome three main potential errors in a standard dipstick test: lighting, volume control and timing.
The approach is inexpensive and reliable, in part because the system is based on the same tried and trusted dipstick used in medical offices, researchers said.
As a colour-based test, the dipstick needs consistent lighting conditions. The same colour can look different depending on its background, so Smith and Bowden created a black box that covers the dipstick. Its flat, interlocking parts make it easy to mail, store and assemble.
"If you have too little or too much urine on the dipstick, you'll get erroneous results," Smith said. 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 colour analysis. nTo 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 programme on their computer. For each pad, it pulls out the frames from the correct time and reads out the results. The research was published the journal Lab on a Chip.
