Researchers from Columbia University have developed a “lab on a chip” HIV and syphilis test, and are now reporting the first results from tests in the field conducted in Rwanda. The mChip, as it is called, is the size of a credit card and replicates all steps of an ELISA test, at a lower total material cost and within 20 minutes. After application of a blood sample, the chip is inserted into a $100 battery-powered handheld analyzer. It needs only 1 ?l of unprocessed whole blood and does not require any user interpretation of the signal, providing a clear-cut yes or no result.
Right now, HIV testing in developing countries either relies on expensive laboratory testing taking a long time, or uses cheaper methods based on lateral flow, which, although very rapid, do not provide very reliable results. The mChip combines the best of both worlds, being rugged, cheap (about $2 to $3), easy to use and not requiring a lot of infrastructure or training. The lab on a chip trial showed an impressive 100-percent detection of HIV-positive cases, with only one false positive out of 70 total samples. With dual HIV and syphilis testing, 94 percent of syphilis cases were detected, with a slightly higher four out of 67 total false positive rate.
The chip could also potentially detect hepatitis B and C, herpes, gonorrhea and chlamydia. All infections could be detected on a single device, at the same time and with a small amount of blood. All together, this chip could be a big win for detection of infectious diseases in remote settings. The design of the chip and the initial field test results were published online in Nature Medicine.
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