According to the World Health Organization, somewhere between 130 and 150 million people around the globe suffer from chronic hepatitis C infection. As the virus is usually asymptomatic it can go undetected in its early stages, giving rise to complications such as liver damage and cirrhosis. Screening for the virus is possible, but is neither straightforward nor widely accessible, as it involves taking a blood sample and two separate lab tests. But researchers have now developed a one-step test that can detect hepatitis C using only a urine sample, promising to boost the availability of diagnosis and efforts to curb the virus around the world.

The current approach to testing for hepatitis C consists of two main steps. A blood sample is drawn and checked for signs of an immune response to the virus, specifically anti-hepatitis C antibodies. But the presence of these antibodies alone doesn't confirm an active infection, as those who have been infected previously but whose body has already killed off the virus of its own accord will still test positive at this stage.

So a second phase of testing, a nucleic acid test for the hepatitis C virus, is needed to ascertain whether the infection is still active. The trouble is, at a cost of more than US$200, many developing countries don't have the resources to offer this second, critical part of the testing. But researchers at the University of California Irvine's School of Medicine say they have developed a one-step approach that allows the virus' antigens to be detected in a urine sample instead.

"Our novel HCV (hepatitis C virus) antigen test system has significantly improved sensitivity and specificity over current tests," says Dr Ke-Qin Hu, professor of gastroenterology and hepatology at University of California Irvine School of Medicine. "Importantly, for the first time, we can use urine specimens for one-step screening and diagnosing of HCV infection."

And because handling urine samples is less complex than blood samples, it could make screening for the virus more widely available.

"The ability to detect infection using urine rather than blood avoids needle stick and blood sample collection, greatly reduces the cost and necessary clinical infrastructure for screening and diagnosis, helping to promote widespread adoption of the test on a global scale," Hu says.

The researchers are presenting their findings at the Annual Meeting of American Association for the Study of Liver Disease (AASLD) in San Francisco, this week.