First smartphone DNA test for chlamydia

Most people with chlamydia are not aware of it because the infection often causes no symptoms, but if left untreated, this STD can develop into pelvic inflammatory disease and irreversibly damage a woman's reproductive system. According to the Centers for Disease Control and Prevention, pelvic inflammatory disease affects up to 30% of women with chlamydia, and can cause infertility; debilitating, chronic pelvic pain; and life-threatening ectopic pregnancies. Over the past decade, healthcare providers have been able to expand screening programs for chlamydia thanks to the development of a highly sensitive method known as nucleic acid amplification testing (NAAT). NAATs are too complex, however, to perform in point-of-care settings such as physicians' offices, health fairs, school clinics, or other sexual health outreach venues, and they also have a high per-test cost.

A team of researchers led by Jeff Tza-Huei Wang, PhD, from the Johns Hopkins University BioMEMS Lab, Baltimore, Maryland have developed the first low-cost NAAT platform that can diagnose chlamydia at the point-of-care and that integrates sample preparation, DNA amplification, and data processing all in one coffee mug-sized instrument. Known as mobiLab, this battery-powered device works by using a microfluidics cartridge to detect the DNA of chlamydia bacteria in genital swab samples. The DNA analysis unit is integrated with a smartphone, which enables the user to control the platform and process test data with an app.

MobiLab's developers validated the test's accuracy by comparing its performance with the Gen-Probe Aptima Combo 2 assay, the gold standard test for chlamydia. After analyzing 20 patient samples using both tests, the researchers found that mobiLab and the Gen-Probe test both identified the same 10 positive and 10 negative cases. This demonstrates that mobiLab can be used in place of standard NAATs. Additionally, each microfluidics cartridge it uses costs less than $2, an order of magnitude cheaper than similar commercial cartridges, which can cost close to $10 per test. Altogether, this will make it possible for a greater number of non-traditional healthcare settings to afford and offer chlamydia testing and to screen a wider portion of at-risk women and men with high precision.

"We now have these pretty accurate, sensitive, and specific molecular assays to detect very few numbers of organisms in biological samples," said Dong Jin Shin, one of the abstract's authors and a PhD student at Johns Hopkins. "But a lot of these technologies are confined to being used in centralized lab settings. If we're able to bring molecular diagnostic technology closer to the clinic and deliver accurate results to clinicians sooner, then we'll be able to improve our standard of care for patients with chlamydia while also saving costs."