HIV USB stick test

HIV USB stick offers fast, accurate way to measure levels of the virus in patients

An HIV testing USB stick that gives fast and accurate readings of the amount of the virus in a patient’s blood has been developed by a team at Imperial College London.

The device needs just a drop of blood to detect HIV, then creates an electrical signal that can be read by a computer, laptop or handheld device.

The disposable test is being touted as a convenient way for HIV patients to monitor their own treatment in a similar fashion to diabetic blood testing kits that allow those with the condition to track their blood sugar levels.

Furthermore, regular monitoring of viral levels enables healthcare teams to check a patient is taking their medication. Stopping medication fuels HIV drug-resistance, which is an emerging global problem.

In addition, sometimes the drugs stop working because the virus develops resistance over time, and the first sign of that would be a rise in a patient’s so-called ‘viral load’ allowing medical teams to quickly transition to a different, more effective drug.

Current AIDS drugs, called anti-retrovirals, reduce virus levels in a patient’s blood to near zero. Virus levels can’t be detected by routine HIV tests, which can only show whether or not a person has the virus.

It could also be particularly useful in remote settings to help HIV patients manage their treatment, since current tests to detect virus levels take at least three days and involve sending a blood sample to a laboratory.

“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,” said Graham Cooke, who co-led the research from the Imperial’s department of medicine.

“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.”

The test, which uses a mobile phone chip, requires a drop of blood to be placed onto a spot on the USB stick. Any HIV in the sample triggers an acidity change, which the chip transforms into an electrical signal. This is sent to the USB stick, which shows the result on a computer or electronic device.

It was shown that the stick test was 95 per cent accurate over 991 blood samples, and the average time to produce a reading was 20.8 minutes.

Some 36 million people worldwide are infected with the human immunodeficiency virus (HIV) that causes AIDS, and the majority of them live in sub-Saharan Africa.

The research team is now investigating whether the device can be used to test for other viruses such as hepatitis.

In August, IBM revealed its ‘lab-on-a-chip’ technology which is designed to separate biological particles at the nanoscale to enable physicians to detect diseases such as cancer before symptoms appear. 

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