urinary tract infections (UTIs) could be detected simply and cheaply using a smartphone camera.

They said their system can detect the disease in just 25 minutes and could enable those in the developing world to be easily diagnosed as it is more portable and cheaper than traditional lab tests.

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, which is present in around 80 per cent of bacterial UTIs.

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. Finally, an enzyme is added that causes a change in colour that can be picked up by a smartphone camera.

The procedure is simple and could be manually operated or fully automated without any need for a mains power supply.

Dr Nuno Reis, from the University of Bath’s Department of Chemical Engineering, led the development of the test.

“The test is small and portable - so it has major potential for use in primary care settings and in developing countries,” Dr Reis said.

“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.”

So far, bodies such as the United States Food & Drug Administration (FDA) have been reluctant to approve medical technology using smartphones over concerns that software updates and variability between models could make such tests unscientific.

But Dr Reis hopes that the way the test uses a variable scale to digitally compare the pixels within an image will convince regulators to allow the treatment to move toward eventual production.

“The UK and wealthy countries have seen a big shift to decentralised diagnostics to reduce the load on national or regional labs and provide doctors with important tools to make informed diagnoses,” he said.

“Driving more of this will bring better outcomes to patients in terms of speeding up the process, but will also lower the cost to healthcare providers.

“We are not talking about replacing centralised diagnostics services but providing the first point of contact with affordable and rapid tools to support prescription of antibiotics and avoid their overuse.”

The next step for the test is clinical trials, which require collaboration with clinical and commercial partners.

The team will also begin working on refining the test to allow for the detection of other bacteria and their concentrations.