HIV testing in one hour or less

Advances in biosensor technology are expected to limit the spread of HIV and other sexually transmitted infections, according to market research firm IDTechEx.

1.8 million people acquire HIV each year, with the World Health Organization (WHO) estimating that one in five people living with HIV do not realise they are infected. Therefore, strategies for faster and earlier diagnosis are as important as ever to limit the spread of HIV.

Currently, the most common test for HIV looks for an immune response by looking for the antibodies the body produces in response to infection. A blood sample taken from the patient is sent to a laboratory for this test, which takes around a week, with positive results then confirmed by a second test. Alternatively, in resource-limited settings where the infrastructure is not available to conduct such tests, lateral flow devices (resembling at-home pregnancy tests) can be used to make an initial diagnosis.

The problem with testing for antibodies (the immune response) is that it can produce false-negatives when the test is conducted before the immune response has occurred. It takes around four weeks for the body to generate antibodies to HIV, called the ‘window period’; therefore, tests cannot be carried out before this time. The advice is to wait three months to take an HIV test.

The most rapid and reliable way of detecting HIV is to search for the HIV genetic material directly in blood, using a process called polymerase chain reaction (PCR). This has the advantage of not requiring a long wait after exposure, being available after only three days.

Traditionally this process, known as molecular diagnostics, has been performed in a laboratory by trained personnel. Recent technological advances have, however, brought the possibility of conducting molecular diagnostics out of the laboratory and next to the patient. This is part of a wider trend in the field of biosensors, which is undergoing a shift to the point of care.

Point-of-care testing can be defined as a test which takes under an hour on a portable device, meaning samples no longer have to be sent to a laboratory for analysis, with the results fed back for follow-up treatment. It has particularly high value in the diagnosis of sexually transmitted infections, where a rapid diagnosis can demonstrably reduce the spread of infection.

The IDTechEx report ‘Biosensors for Point-of-Care Testing 2017–2027’ gives a complete analysis of the important trends in the field of medical biosensors and lists the new technologies and devices which are likely to be highly disruptive to the in vitro diagnostics market. With the ability to carry out tests while the patient waits, treatment can be given immediately and the spread of infection is greatly reduced.

The report is available at the IDTechEx website.

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