Now You Can Test Your Urine With Your Smartphone

Stanford engineers create a simple and reliable urinalysis system that can be used at home using a standard dipstick that changes color, and a smartphone to analyze the results.

Kristopher Sturgis

For decades the standard dipstick test has been used to test urine for the presence of different biomarkers like proteins, glucose, and pH balance to help doctors detect infection. The test can be read in as little as two minutes after dipping, and has become common practice in clinics all over the world. Unfortunately, like many things, the test requires time and money--leaving many clinics backed up with samples waiting to be handled and diagnosed.

Recently, researchers have begun to search for low-cost alternatives that are as reliable as they are convenient. This week, Stanford University engineers created a new device that couples with your smartphone--enabling patients to use the dipstick test in any environment, even their own home.  Audrey (Ellerbee) Bowden, an assistant professor of electrical engineering at Stanford, designed the new portable device along with Gennifer Smith, a PhD student in electrical engineering at the university.

"We imagine this device being used to reduce the burden on laboratories," Bowden says. "The frequency of negative test results is a significant burden on the healthcare system. We also imagine the device could be used by people who suffer from chronic diseases and need to track their urinalysis results over time, or need frequent prescriptions that are only available after the doctor runs a dipstick test and sees a positive result."

The key for these engineers was to develop a system that could work with the standard dipstick that is used and trusted by doctors everywhere. The test consists of a paper strip with 10 different pads imbued with chemicals that react and change color when they interact with compounds present in urine. User error usually enters the equation during the process of loading and reading the dipstick, which is why many doctors insist on testing samples in a clinical environment.

"The dipstick test is advantageous because it is cheap and quick to run," Bowden says. "Unfortunately, the process for using a dipstick has many aspects that are prone to user error, which can result in erroneous results reported by the user. For this reason, doctors have a hard time trusting the results from tests performed at home."

Bowden says their new device could serve as a cost-effective solution that addresses the three main concerns when it comes to user-prone error: lighting, volume, and timing.

"With our device we control the processes of dipstick urinalysis that are susceptible to user error," she says. "We control the lighting, volume, and timing aspects of the test. Other technologies only account for a subset of these user-prone aspects. We are also using commercially-available dipsticks, so we are using a chemistry for urinalysis that is already being used in the clinic."

To address volume, the engineers created a multi-layered system that deposits urine onto the dipstick. First, a dropper loads urine into a hole in the first layer, before filling up a channel in the second layer. Finally, 10 square holes are filled in the third layer, which is then inserted into a black box, ensuring a standardized volume of urine is deposited on each dipstick pad. The final step in the process involves placing a smartphone on top of the black box with the smartphone video camera focused on the dipstick inside. The phone then runs custom software to read video from the smartphone and analyze the dipstick for results.

"Using the video collected from a smartphone allows our software to ensure that the tests are read at the correct time, and also automatically compares the colors present in the dipstick with a reference chart provided by the manufacturer," Bowden says. "This obviates the need for the user to differentiate between different shades of color in a timely manner, which is a significant source of user error."

The device is just the latest in medtech innovations that looks to use smartphones to empower patients with advanced medical technologies. Last year engineers developed a smartphone dongle that can detect and diagnose HIV in just 15 minutes. Elsewhere, researchers from the University of Houston devised to turn any smartphone into a microscope through an optical lense that attaches to your smartphone, amplifying images by a magnitude of 120.

These Stanford engineers also hope to use smartphones to enhance their device, and eventually develop an app that can read the results, and immediately send them directly to the doctor. This would remove the need for countless patients making trips to the clinic just for a simple urine test, as well as open up clinical and laboratory resources that are spent logging and handling a myriad of different urine samples. The device could even evolve to detect other diseases as dipstick technologies advance.

"The device we built is very easy and cost-effective to manufacture," Bowden says. "The whole system costs less than a dollar, and is reusable. Our device can also easily adapt to work with new dipsticks that may be developed for detecting new diseases, and we do have plans to enhance the technology to deal with other aspects of urinalysis." 

Kristopher Sturgis is a contributor to Qmed.

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