Smartphone Accessory Rapidly Diagnoses HIV and Syphilis
Using a single finger prick of blood, a revolutionary new smartphone accessory can detect markers for HIV and syphilis in just 15 minutes at an extremely low cost, according to new research in Science Translational Medicine.
Samuel K. Sia, Ph.D., an associate professor of biomedical engineering at Columbia Engineering in New York, led the team of researchers who developed the dongle—a small device that connects to a computer or smartphone.
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The device detects three infectious disease markers not currently available in a single test format:
• HIV antibody.
• Treponemal-specific antibody for syphilis.
• Non-treponemal antibody for active syphilis infection.
“The dongle presents new capabilities for a broad range of users due to its simplicity and user-friendliness,” says study co-author Tassaneewan Laksanasopin, a doctoral student who worked on Sia’s team. “Smartphone accessibility is increasing worldwide. Our technology allows almost any population who has access to a smartphone to access laboratory-based diagnostics at the point of care.”
Sia’s team collaborated with researchers from Columbia’s Mailman School of Public Health; the Rwanda Biomedical Center’s Institute of HIV Disease Prevention and Control; Columbia University Medical Center’s Department of Pathology and Cell Biology; the Laboratory Reference and Research Branch of the Centers for Disease Control and Prevention; and OPKO Diagnostics.
Health care workers in Rwanda performed pilot testing of the dongle, testing whole blood from a finger prick of 96 patients who enrolled to receive care at prevention-of-mother-to-child-transmission clinics or voluntary counseling and testing centers.
As part of the field testing, the workers received 30 minutes of training on how to use the test, including a user-friendly interface to guide users through each test, illustrated step-by-step directions, built-in timers to alert users about when to move to the next step, and records of test results for later review.
In just 15 minutes, they obtained diagnostic results with a sensitivity of 92% to 100% and specificity of 79% to 100%—a level of accuracy that rivals the gold-standard laboratory tests that are currently used.
“This low-cost smartphone dongle replicates all mechanical, optical, and electronic functions needed for a full laboratory-quality immunoassay without requiring any stored energy,” Laksanasopin explains. “All necessary power is drawn from a smartphone via audio jack.”
Nearly all patients (97%) said they preferred the dongle to laboratory-based tests because of its quick turnaround time, simplicity, and the convenience of testing for multiple diseases with just one finger prick.
“Currently, all these tests are not done at the first visit, our multiplexed test can simplify the workflow for health care workers and ensure prompt diagnosis and care for patients,” Laksanasopin says. “Early diagnosis and treatment of sexually transmitted diseases in pregnant mothers can greatly reduce adverse consequences to both mothers and their babies.”
This technology could revolutionize the way infectious disease testing is conducted worldwide, especially in areas with poor access to health care.
The estimated cost of the dongle is just $34, with each test cassette costing about $2. The process requires little user training and the device can be attached to any compatible smart device by plugging into the audio jack.
“We are planning to conduct a larger-scale trial, obtain WHO approval, and get the device to the market in the developing countries in the next few years,” Laksanasopin says.
—Colleen Mullarkey
Reference
Laksanasopin T, Guo TW, Nayak S, Sridhara AA, Xie S, Olowookere OO, et al. A smartphone dongle for diagnosis of infectious diseases at the point of care. Sci Transl Med. 2015 Feb 4;7(273):273.