News & Updates

30-minute urine test to measure levels of substances that can contribute to kidney stones

Researchers from Penn State and Stanford University have developed a 30-minute urine test to measure levels of substances that can contribute to kidney stone formation. The test could help patients to find out if they are prone to developing kidney stones or to monitor their progress in avoiding kidney stone formation through treatment or dietary changes.

Kidney stones are accumulations of crystallized substances such as minerals and salts, and the stones can cause pain and blockages in the urinary system. Certain people are prone to developing the stones, and assessing urinary levels of these substances is key in monitoring their risk of stones in the future.

However, the current urinary test for these substances is cumbersome and time consuming. Patients must collect a significant quantity of urine over a 24-hour period, and then send the large urine sample off to a laboratory with expensive specialized testing equipment, before receiving the results about a week later.

“The lengthy process, cumbersome collection procedure and delay in obtaining the results render 24-hour urine testing to be underutilized in clinical practice despite guideline recommendations,” said Pak Kin Wong, a researcher involved in the study.

To address this, this group of researchers has developed a rapid test that takes only 30 minutes and can be performed in a doctor’s office, or even at home, without any specialized equipment. The test uses bioinspired low-friction surfaces, similar to those seen in carnivorous plants that cause insects to slip to their death. The aim is to improve liquid movement through a small plastic device, leading to its name, slippery liquid-infused porous surface (SLIPS)-LAB.

A small urine sample is added to the device and surface tension draws droplets of the sample through the plastic channels, which are low-friction and allow the droplets to move easily. The droplets combine with specific reactants within the device and the results can be assessed using a cell phone camera.

“We demonstrated that SLIPS-LAB enables the reagent and sample to move themselves and perform the reactions for us,” said Wong. “It means the technology doesn’t require a technician to run any test machinery, so it is possible to do the test in non-traditional settings, like a physician’s office or even the patient’s home.”