New Smartphone DNA Test for Chlamydia is Fast, Inexpensive

A novel smartphone test that can detect chlamydia with high accuracy could reduce the cost and burden of screening for this highly prevalent sexually transmitted disease, according to new data presented last week at the 2015 American Association for Clinical Chemistry (AACC) Annual Meeting & Clinical Lab Expo in Atlanta.

“We think this platform can be easily incorporated into a wide range of settings, including local pharmacy and outpatient clinics that do not have access to diagnostic tests,” says investigator Dong Jin Shin, a PhD student at Johns Hopkins University who presented the research at AACC.
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“For communicable diseases such as bacterial infection (of which chlamydia is one), the ability to perform sensitive tests on site can save a lot of time, especially in areas where timely access to central laboratory facilities is not trivial,” Shin says. “Reducing the time it takes for test results to reach the doctor and their patients could save the patients the time and cost associated with an extra visit.”

Shin and a team of researchers led by Jeff Tza-Huei Wang, PhD, from the Johns Hopkins University BioMEMS Lab, in Baltimore, Md., developed the MobiLab platform, which integrates sample preparation, DNA amplification, and data processing into one device that’s about the size of a coffee mug.

Using a USB power source, this highly portable test can diagnose chlamydia at the point-of-care and can detect the presence of the DNA of chlamydia bacteria in genital swab samples with a microfluidics cartridge. In addition to the cartridge, the test also consists of a peripheral instrument for the smartphone and a smartphone application.

The cartridge contains all reagents for sample processing and detection, which is automated via the peripheral instrument. The smartphone is used as the user interface and an optical sensor, as the developing signal from the cartridge is registered using the operator’s smartphone camera.

“This test integrates many components together into a single process using devices that are familiar to us in our daily lives, and we believe it has the potential to make DNA amplification tests more convenient and accessible than ever before,” Shin says.

The team validated the MobiLab platform’s accuracy by comparing its performance with the Gen-Probe Aptima Combo 2 assay, the current gold standard in chlamydia testing. Both tests correctly identified the same 10 positive and 10 negative cases out of the 20 patient samples they analyzed.

“The bill of materials for the prototype instrument stands at less than $200 using off-the-shelf components,” Shin says. “Each test cartridge currently stands at just below $2 per test using off-the-shelf reagents and material, which should be substantially cheaper than existing tests by at least an order of magnitude.”

The team is currently working on verifying test performance through field studies in collaboration with researchers at the Johns Hopkins School of Medicine.

“Both academic and industry players are actively pursuing DNA amplification-based molecular testing as we speak, and I would not be surprised to see these products incorporated into our standards of care within the next 5 years,” Shin says.

—Colleen Mullarkey

Reference

Shin D, Athamanolap P, Chen L, Hardick J, Gaydos CA, Wang T. Clinical evaluation of mobiLab, a smartphone-enabled microfluidic NAAT platform for Chlamydia trachomatis screening. Presented at the 2015 AACC Annual Meeting & Clinical Lab Expo, Atlanta, Ga. 2015 July 29;B-231.