Miniature Test Device Rapidly Measures Patient HIV Load

A device for measuring levels of HIV virus particles has been built into a USB stick for rapid use by an individual to monitor his/her viral load or as an alternative to laboratory instrumentation in remote locations.

Viral levels cannot be detected by routine HIV tests, which use antibodies to detect whether a person has been infected. To measure viral levels, investigators at Imperial College London (United Kingdom) incorporated a pH-mediated, point-of-care HIV-1 viral load-monitoring assay that simultaneously amplified and detected HIV-1 RNA onto a metal-oxide semiconductor (CMOS) chip. The investigators used the device to screen 991 clinical single-drop-of-blood samples.

Results revealed a sensitivity of 95% (in vitro) and 88.8% (on-chip) at more than1000 RNA copies/reaction across a broad spectrum of HIV-1 viral clades. Median time to detection was 20.8 minutes in samples with more than 1000 RNA copies.

Senior author Dr. Graham Cooke, professor of medicine at Imperial College London, said, "HIV treatment has dramatically improved over the last 20 years - to the point that many diagnosed with the infection now have a normal life expectancy. However, monitoring viral load is crucial to the success of HIV treatment. At the moment, testing often requires costly and complex equipment that can take a couple of days to produce a result. We have taken the job done by this equipment, which is the size of a large photocopier, and shrunk it down to a USB chip."

Details of the device were published in the November 10, 2016, online edition of the journal Scientific Reports.

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