A new smartphone accessory developed at Columbia University is fast, accurate, affordable, and doesn't require a power source.
Scientists from Columbia University in New York City tested their new, accurate, fast, and ridiculously inexpensive point-of-care test for HIV and syphilis in Kigali, a densely populated city in Rwanda. With frequent power outages and annual health expenditure per capita of only US $66, expensive tests that require electricity are not always feasible.
In Rwanda, the prevalence of adults living with HIV/AIDS is 2.9% (compared to 0.8% globally). The prevalence of syphilis in Rwanda among women seeking antenatal care is 2.65% (compared to 1.65% globally), Syphilis, a severe, disabling infection often with grave consequences for infants is transmitted from an infected mother to the unborn infant through the placenta. Unlike HIV/AIDS, syphilis is relatively easy to treat with antibiotics.
Nicknamed the Country of Thousand Hills, Rwanda is situation in the Great Lakes Region of Africa. In 2013, the average life expectancy was just over 59 years. Although the annual per capita income is only US $634, according to World Bank data, approximately 55 per 100 Rwandans had mobile phone subscriptions.
Source: oledle (Flickr: CC)
All these factors weigh on the minds of scientists seeking to innovate the detection and, possibly, improve outcomes in places like Rwanda. “There’s no question that this type of test is really needed in the developing world,” says Dr. Sam Sia, Associate Professor of Biomedical Engineering at Columbia University. “But the question is can we actually develop the test to a point that it can be made available at a sufficiently low cost?”
The Quest for a Better Test
Sia has spent his career developing portable, less expensive alternative testing techniques for communicable diseases. The results of his most recent experiment were published in the Science Translational Medicine journal this month.
Sia and his team from Columbia University designed a test for HIV and syphilis using smartphone attachment (a dongle), a finger-stick of blood, and very small amounts of silver and gold. The dongle diagnoses HIV and/or syphilis in 15 minutes or less, and at a fraction of the cost.
For an estimated manufacturing cost of $34, the invention runs a full, labroartory-quality immunoassay on a smartphone accessory. This compares to $18,450 for the more typical enzyme-linked immunosorbant assay (ELISA) equipment.
Sia’s dongle is exceptionally innovative. It is the first to perform triplexed immunoassay (i.e., HIV antibody, treponemal-specific antibody for syphilis, and nontreponemal antibody for active syphilis infection) in a single test format.
The dongle blood test requires less training to perform, less time to run, and a significantly smaller blood sample. Powered by a one-push vacuum start and the stored power in a smartphone’s audio jack, the test for HIV and syphilis requires less power than running a smartphone on standby.
Patients Liked the Speed of the Dongle Test, and It Hurt Less
In the Columbia study, community healthcare workers were trained to use the dongle and smartphone app in approximately 30 minutes. The app walks users through each test with step-by-step pictorial instructions, timers to indicate when to move to the next step, and records of the test for later review.
Community health workers used the dongle to test whole blood obtained by a finger prick from 96 patients who had enrolled for preventive care at mother-to-child transmission clinics or voluntary counseling and testing centers in Kigali. In terms of sensitivity and specificity, the dongle test results were not significantly different than the much more expensive ELISA methods.
Most of the patients would recommend the dongle to others because of the fast turnaround time, potential to offer results for multiple diseases, and the simplicity of the procedure, according to a survey of study participants. Obtaining blood via finger prick was also preferred to the traditional blood draw because it was less painful and took less time. Only 2% of patients preferred venipuncture as they trusted the result more if venous blood was used.
Healthcare workers reported that the dongle was easy to use, and its results easy to read. They also thought freedom from a power-source would be useful in their work, where the dongle might replace traditional ELISA in low-volume clinics, or be used as a back-up for high volume clinics in case of power outages.
“We are really excited about the next steps in bringing this product to the market in developing countries,” Sia comments. “And we are equally excited about exploring how this technology can benefit patients and consumers back home.”