US scientists have found a new method of screening for HIV/AIDS and hepatitis C is making the blood supply safer.

The National Institute of Health says the nucleic acid-amplification testing detects the virus in instances where its concentration is too small to be picked up by other screening methods.

The new method reduced the risk of HIV/AIDS and hepatitis infections to about one in two million units of blood, compared with one in 1.5 million for HIV and one in 276,000 for hepatitis when less comprehensive screening methods were used.

It is also effective in detecting emerging viruses. Researchers say it detected traces of the West Nile virus in blood from nearly 1,000 donors last year.

The test is carried out on around 98 percent of the blood collected in the United States.

Source: CRI