An international team has developed the prototype CD4 rapid test, similar in design to a home pregnancy test, which works with a finger-prick blood sample to measure the numbers of CD4+ T-cells in a person's blood.

CD4+ T-cells are critical for a healthy functioning immune system and are slowly destroyed during the course of an HIV infection, thereby making patients increasingly vulnerable to illness.

According to lead scientist Professor Suzanne Crowe of Burnet Institute, the test enables patients at the point of care to find out within just 30 minutes if they should begin antiretroviral treatment without any laboratory equipment being required.

The majority of patients in developing countries start antiretroviral therapy based on symptoms alone. Research shows that if HIV patients wait till they're sick to start treatment they have a much poorer outcome than if treatment were started based on a CD4 count.

The majority of patients in the developing world don't currently have access to CD4 testing as it is expensive, and relies on sophisticated laboratory testing requiring specially trained operators.

Where testing facilities exist, it is often too difficult for people in rural areas to access them and it can take weeks to obtain results. Currently 33 million people globally have been diagnosed with HIV, many of them in resource poor countries.