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Low-cost ELISA device allows rapid HIV diagnosis in resource-limited settings

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Mobile lab-on-a-chip rapidly diagnoses sexually transmitted infections and synchronizes patients’ electronic medical records via satellite communication.

A team led by Samuel Sia of Columbia University (New York, NY, USA) have engineered and successfully tested a rapid, low-cost mobile ELISA device for the diagnosis of HIV, hepatitis and other sexually transmitted infections. The lab-on-a chip requires little user input and delivers a diagnosis ten times faster than a benchtop ELISA, whilst using satellite communication to instantly update the patient’s medical record.

The device, known as the mChip, uses miniaturized ELISA technology, runs on the amount of energy required to power a mobile phone and links to the patient’s medical records via satellite, synchronizing the device’s diagnosis with the electronic cloud-based records in real time. The device was tested in Rwanda, using serum, plasma and whole blood samples to perform serodiagnostic testing of HIV and hepatitis. The device was used to diagnose HIV in 167 Rwandan patients, resulting in a diagnostic sensitivity and specificity of 100% and 99% respectively. The researchers also tested 40 samples of whole blood from Rwandan patients: using 1 μl of blood resulted in diagnostic sensitivity and specificity of 100 and 100%, respectively.

The study’s lead author, Sia, said, “We’ve built a handheld mobile device that can perform laboratory-quality HIV testing, and do it in just 15 minutes and on finger-pricked whole blood. And, unlike current HIV rapid tests, our device can pick up positive samples normally missed by lateral flow tests, and automatically synchronize the test results with patient health records across the globe using both the cell phone and satellite networks.”

The mChip returns its diagnosis in 15 min, which is a significant improvement on the 3 hours required by a benchtop ELISA. Sia’s team compared their device’s efficacy to a leading benchtop ELISA by testing a commercially-available sample panel of mixed antibody titers. The researchers found that for all samples in the panel, the mChip gave results which agreed with the benchtop ELISAs and indeed was able to detect positive results in some weakly positive samples for which the benchtop ELISA indicated false negatives.

“There are a set of core functions that such a mobile device has to deliver,” Sia says. “These include fluid pumping, optical detection, and real-time synchronization of diagnostic results with patient records in the cloud. We’ve been able to engineer all these functions on a handheld mobile device and all powered by a battery.”

This device has the potential to allow low-resource areas access to laboratory-quality diagnostic testing, previously available only in developed countries. Sia worked with a company he co-founded, OPKO Diagnostics, to develop the microfluidic-based diagnostic device. Sia’s group worked together with OPKO Diagnostics, ICAP (Columbia University Mailman School of Public Health), the Rwandan Ministry of Health and collaborators from the Muhima Hospital and two health clinics in Rwanda. The work was funded by US$2 million Saving Lives at Birth transition grant.

Jessica Justman is the Senior Technical Director of ICAP. She says, “This is an important step forward for us towards making a real impact on patients. And with the real-time data upload, policymakers and epidemiologists can also monitor disease prevalence across geographical regions more quickly and effectively.”

Sia reports that his next step will be to develop a diagnostic panel to test for HIV and other sexually transmitted infections in pregnant women in Rwanda. The technology could also be implemented in personal health care for consumers in the USA.

Sia says, “This work takes us another step closer to offering automated clinical laboratory diagnostic tests for physicians, clinicians and patients. The automation includes not only running the test but also connecting the results to the cloud. We are working to make the mChip immunoassay available to the end users, as well as adding other classes of assays to the panel.”

Sources: Chin CD, Cheung YK, Laksanasopin T et al. Mobile Device for disease diagnosis and data tracking in resource-limited settings. Clin. Chem. doi:10.1373/clinchem.2012.199596 (2013) (Epub ahead of print); Handheld device brings fast HIV testing to remote areas.

 

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