Several organisations have recommended scaling up screening for hepatitis C infection. But experts writing in The BMJ this week warn that no study has tested whether this will lead to net clinical benefit or harm.
Ronald Koretz, emeritus professor at UCLA School of Medicine and colleagues say physicians "should resist screening until we have strong evidence that antiviral therapy is clinically effective and the benefits outweigh the harms."
Hepatitis C is a virus that can infect and damage the liver.
In 2012, the advent of new treatments led the US Centers for Disease Control and Prevention (CDC) to recommend screening everyone born during 1945-65 since it estimates that three quarters of all people infected are in that age group.
Widespread screening is also endorsed by the US Preventative Services Task Force and the World Health Organization, as an opportunity to save hundreds of thousands of lives worldwide by preventing end stage liver disease.
But Koretz and colleagues argue that most hepatitis C patients "will not develop end stage liver disease and will therefore be unnecessarily treated."
They question the validity of using surrogate markers in drug trials to predict long term effects of treatments. And say the ability of therapy to reduce the incidence of end stage liver disease is unproved.
"Given the uncertainty about the validity of the surrogate markers, the lack of evidence regarding clinical outcomes of treatment or of screening strategies, and the adverse events caused by the newer regimens, screening may be premature," they write.
"Physicians should resist screening until we have strong evidence that antiviral therapy is clinically effective and the benefits outweigh the harms," they conclude.