Smartphone device can diagnose HIV in 15 minutes

A team of researchers from Columbia University has developed a low-cost smartphone accessory or dongle that can perform a test that simultaneously detects three infectious disease markers from a finger prick of blood in just 15 minutes.

Led by Samuel K. Sia, associate professor of biomedical engineering at Columbia's School of Engineering and Applied Science, the device replicates for the first time all mechanical, optical, and electronic functions of a lab-based blood test.

Specifically, it performs an enzyme-linked immunosorbent assay (ELISA) without requiring any stored energy as all necessary power is drawn from the smartphone.

"It performs a triplexed immunoassay not currently available in a single test format, HIV antibody, treponemal-specific antibody for syphilis, and non-treponemal antibody for active syphilis infection," Sia explained.

The small device that easily connects to a smartphone or computer was recently piloted by health care workers in Rwanda who tested whole blood obtained via a finger prick from 96 patients.

"A full laboratory-quality immunoassay can be run on a smartphone accessory," Sia noted. This kind of capability can transform how health care services are delivered around the world.

Early diagnosis and treatment in pregnant mothers can greatly reduce adverse consequences to both mothers and their babies.

The team developed the dongle to be small and light enough to fit into one hand and to run assays on disposable plastic cassettes with pre-loaded reagents, where disease-specific zones provided an objective read-out, much like an ELISA assay.

Sia estimates the dongle will have a manufacturing cost of $34, much lower than $18,450 that typical ELISA equipment runs.

During the field testing in Rwanda, the vast majority of patients (97 percent) said they would recommend the dongle because of its fast turn-around time, ability to offer results for multiple diseases and simplicity of procedure.

"By increasing detection of syphilis infections, we might be able to reduce deaths by 10-fold. We might be able to scale up HIV testing at the community level with immediate antiretroviral therapy that could nearly stop HIV transmissions and approach elimination of this devastating disease," the authors concluded.

The work was published in the journal Science Translational Medicine.