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Carrying out HIV tests is a challenge in remote areas where there is limited availability of all the required equipment, but that could change soon with a new USB stick based test the can detect HIV in just 30 minutes.

Developed by a team of researchers including those from Imperial College London and DNA Electronics, the new USB stick based HIV test can detect HIV with just a drop of blood. Researchers are optimistic that this particular test could one day be available off the shelf and can be used by patients themselves to monitor the levels of the virus in their blood.

In the study published in journal Scientific Reports researchers point out that the timely detection of viremia in HIV-infected patients receiving antiviral treatment is key to ensuring effective therapy and preventing the emergence of drug resistance. In high HIV burden settings, the cost and complexity of diagnostics limit their availability, the authors add.

For this reason, researchers have developed a novel complementary metal-oxide semiconductor (CMOS) chip based USB test kit that uses just a drop of blood to detect whether the subject is HIV positive or not in less than 30 minutes.

Researchers point out that current used tests take at least three days to reveal the results and there are parts of the world where such tests aren’t even available. The current treatment for HIV, called anti-retroviral treatment, reduces virus levels to near zero. However, in some cases the medication may stop working – perhaps because the HIV virus has developed resistance to the drugs. The first indication of this would be a rise in virus levels in the bloodstream.

Regular monitoring of virus levels is key to effective mediation and the latest test could enable patients to determine for themselves about the levels of virus in their blood. Viral levels cannot be detected by routine HIV tests which use antibodies, as these can only tell whether a person has been infected.

Researchers are optimistic that their technology could allow patients to regularly monitor their virus levels in much the same way that people with diabetes check their blood sugar levels.

The technology could be particularly powerful in remote regions in sub-Saharan Africa, which may not have easy access to testing facilities. Finding out quickly if a patient, particularly a baby, is infected with the virus is crucial to their long term health and survival.

The device, which uses a mobile phone chip, just needs small sample of blood. This is placed onto a spot on the USB stick. If any HIV virus is present in the sample, this triggers a change in acidity which the chip transforms into an electrical signal. This is sent to the USB stick, which produces the result in a programme on a computer or electronic device.

In the latest research, the technology tested 991 blood samples with 95 per cent accuracy. The average time to produce a result was 20.8 minutes.

The team are also investigating whether the device can be used to test for other viruses such as hepatitis. The technology was developed in conjunction with the Imperial spinout company DNA Electronics which is using the same technology to develop a device for detecting bacterial and fungal sepsis and antibiotic resistance.

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