With just a finger prick, doctors can diagnose HIV and syphilis in only 15 minutes.
Researchers at Columbia University have created an inexpensive smartphone accessory that they say delivers the same mechanical, optical, and electronic functions as laboratory blood tests.
The device, or dongle, performs an enzyme-linked immunosorbent assay (ELISA) using power from the phone. The dongle can also be attached to a computer.
The dongle can test for the HIV antibody, treponemal-specific antibody for syphilis, and nontreponemal antibody for active syphilis infection.
Currently, that type of assessment isn’t available in a single-test format. In fact, it otherwise might require multiple visits to a clinic to get the results.
The dongle runs tests using disposable plastic cassettes with preloaded reagents, where disease-specific zones provide an objective readout, similar to an ELISA assay.
The dongle is affordable as well as effective, researchers say. The triplex test had a sensitivity of 92 to 100 percent and specificity of 79 to 100 percent. It’s expected to cost about $34 to make, compared to $18,450 for standard ELISA equipment.
Device Tested in Rwanda
Dr. Samuel K. Sia, associate professor of biomedical engineering at Columbia University, led the project with several other organizations, including the Centers for Disease Control and Prevention (CDC). Their report was published in Science Translational Medicine.
Sia tested the dongle with a team of healthcare workers in Rwanda. They looked at results from 96 women enrolled in a program to prevent mother-to-child disease transmission.
As part of the pilot, healthcare workers received 30 minutes of training.
Sia said 97 percent of patients indicated they would recommend the device because it was easy to use, had a quick turn-around time, and had the ability to pinpoint multiple diseases accurately.
"Our work shows that a full laboratory-quality immunoassay can be run on a smartphone accessory," Sia said. "This kind of capability can transform how healthcare services are delivered around the world."
He added the dongle can help simplify the workflow and minimize workloads in developing countries where healthcare providers are limited.
“We’ve built a handheld mobile device that can perform laboratory-quality HIV testing, and do it in just 15 minutes and on finger-pricked whole blood,” Sia says. “[It can] automatically synchronize the test results with patient health records across the globe using both the cell phone and satellite networks,” he added.
Energy Smart and Effective
Because some places in developing countries do not have electrical service operating all day, the researchers used a “one-push vacuum” in the device. That allows users to activate a negative-pressure chamber to move the reagents that are stored on a cassette.
They also made it compatible with iPhone and Android platforms.
Sia said the dongle can be used by healthcare workers and consumers. Right now, the focus is mainly on healthcare workers, although researchers want to see how it could be adapted for consumers in developing countries.
"The ability to perform state-of-the-art diagnostics on mobile devices has the potential to revolutionize how patients manage their health,” Sia said.