Novel smartphone test can spot urinary tract infections in minutes

Scientists have developed a new smartphone-based test that could help diagnose urinary tract infections (UTIs) in just 25 minutes. Similar in principle to a pregnancy test, the process can identify the presence of harmful E. coli bacteria in a urine sample using a smartphone camera, according to the researchers from the University of Bath in the UK.

As well as being far faster than existing testing, the test could make accurate UTI diagnosis more widely available in developing nations and remote regions, thanks to its potential to be made portable, and far more cheaply than existing lab-based tests, they said.

E. coli is present in 80 per cent of bacterial UTIs, so if it is found it tells medical professionals that an antibiotic treatment is needed. As well as a smartphone camera, the test, which could be adapted to detect a variety of bacterial infections, takes advantage of widely-available reagents and new micro-engineered materials.

Researchers said the simplicity of the test, which has now passed the proof-of-concept stage, could deliver a new way to quickly identify treatments for patients in poorer or remote regions. Described in the journal Biosensors and Bioelectronics, the test uses antibodies to capture bacterial cells in very thin capillaries within a plastic strip, detecting and identifying the cells optically rather than through the microbiological methods currently used.

“The test is small and portable — so it has major potential for use in primary care settings and in developing countries,” said Nuno Reis, from the University of Bath.

“Currently, bacterial infections in UTIs are confirmed via microbiological testing of a urine sample. That is accurate, but time-consuming, taking several days. We hope that giving medical professionals the ability to quickly rule in or rule out certain conditions will allow them to treat patients more quickly and help them make better decisions about the prescription of antibiotics,” Reis said.

The lack of rapid diagnostics for UTIs has in many cases led to a catch-all prescription of potentially unnecessary antibiotics, which increases the risk of bacteria becoming resistant to treatment — one of the biggest threats to global health and development, researchers said.

The test is carried out by passing a urine sample over a ridged plastic micro-capillary strip, containing an immobilising antibody able to recognise E. coli bacterial cells. If E. coli is present in the sample, antibodies in the reagents will bind with it, stopping it from passing through the section of plastic strip.

An enzyme is then added that causes a change in colour that can be picked up by a smartphone camera, the researchers said. The system also measures the concentration of E. coli in the sample by analysing an image taken by the camera, researchers said.

The procedure is simple and could be manually operated or fully automated without any need for a mains power supply, they said. The next step for the process is clinical trials, which will require collaboration with clinical and commercial partners, the researchers said.