Smartphone dongle developed to test for HIV and syphilis
Researchers from Colombia University have developed a device that can be plugged in to a smartphone, and has the ability to test for both HIV and syphilis. The dongle can conduct point-of-care testing from a finger prick of blood, using cheap and disposable cartridges, delivering a result in just 15 minutes, and at a fraction of the cost of a typical HIV test.
The dongle is a small device that is easily connected to a smartphone or computer, which can perform all of the functions of lab-based diagnostics – without the significant cost. The dongle identifies HIV antibodies in the same way as the ELISA test – a standard HIV antibody test. Uniquely, it also tests for two antibodies specific to syphilis. This triplex immunoassay test is currently not commercially or clinically available as a single test. The estimated cost per dongle is US$34, compared to $US 18,450 for typical ELISA equipment.
The dongle was piloted in Rwanda, with 96 patients undergoing voluntary counselling and testing (VCT) for HIV, as well as expectant mothers enrolled in prevention of mother-to-child transmission (PMTCT) services. Healthcare workers with no experience with ELISAs were given 30 minutes training on how to use the dongle and the dongle app – demonstrating its ease of use. The triplex immunoassay test was compared to the standard ELISA test for HIV, as well as rapid plasma regain, used for syphilis screening. They found that the triplex was nearly as effective as the results of an ELISA test, and well within the clinical guidelines of acceptability for such testing. The test has a sensitivity of 92 to 100 percent, and a specificity of 79 to 100 percent. Of the patients enrolled in the study, 97 percent would recommend the dongle to others because of the rapid results, the ability to identify multiple infectious diseases, and ease of use.
The test represents an important development for low-resource settings in its ability to offer health testing without laboratory diagnostics, or the need for highly skilled care workers, and with minimal electrical power. Harnessing the power of technology for public health benefit is an increasing trend, but mainly for data communications, as opposed to diagnostic assays. Samuel K. Sia, the lead researcher behind the development, stated: “Coupling microfluidics with recent advances in consumer electronics can make certain lab-based diagnostics accessible to almost any population with access to smartphones. This kind of capability can transform how health care services are delivered around the world."