Without viral load tests combination therapy might never have been developed or understood.

In 1995 viral load tests could only measure down to 10,000 copies/mL. By 1996-7 the next generation of tests could measure down to 400 or 500 copies/mL. Since 1998 the most routinely used tests can measure down to 40 or 50 copies/mL.

Tests used for research are even more sensitive (down to 5 or even 1 copy/mL).

In the 1990s, viral load tests were a new technology being developed as a research tool.

Before viral load tests, many researchers thought that HIV had a dormant period.

Viral load tests showed that HIV is never a dormant infection. It is a gradually progressive viral infection that is always active.

They also are a direct marker for researchers to track the impact of each new drug. Without viral load you would have to wait for months to see whether there was an impact on CD4 counts.

When viral load tests were first developed many doctors thought that it would be impossible to measure the progress of a disease on an individual patient level.

Viral load tests now allow doctors to do this.