Geneva: The World Health Organization (WHO) called on Wednesday for an immediate ban on the use of blood tests to detect active tuberculosis, saying they produced wrong results and left millions of lives at risk.
And in unusually frank terms, the U.N. agency suggested that mainly Western test-kit manufacturers misled their customers in developing countries with unfounded claims about their worth and used "perverse financial incentives" to boost sales.
A year-long rigorous analysis by its own and independent health experts uncovered "overwhelming evidence....that the blood tests produced an unacceptable level of wrong results," a statement from the WHO said.
In at least 50 percent of cases, the tests only used in developing countries and mainly in the private sector found sick people to be TB-free and healthy people to have the disease, the agency`s Mario Raviglione told a news conference.
"This means that tens of thousands of people with TB get no treatment, so they are highly likely to infect many, many others," he said. "And a similar number of healthy people are given useless treatment."
The tests, which have no regulatory approval anywhere and are not used in richer nations, "must be stopped immediately and everywhere," Raviglione said.
It is the first time the WHO has issued an explicit "negative" policy recommendation against a practice used in the care of TB which kills 1.7 million people a year.
At least two million of the tests are carried out each year in some 17 poorer countries -- including China and India -- almost exclusively in the private or semi-private sector, according to the WHO.
WHO TB specialist Karin Weyer told the news conference that the WHO had been asked by the government of India to launch a detailed analysis of the tests -- on sale since the mid-1990s.
They were often "targeted at countries with weak regulatory mechanisms for diagnostics, where questionable marketing incentives can override the interests of patients," Weyer said.
"It is a multi-million dollar business centered on selling sub-standard tests with unreliable results."
A separate WHO policy statement said most of the tests "have no published evidence to support their claims of accuracy.
And it declared that there were "perverse financial incentives that may encourage the blood tests to be used by doctors, laboratories, diagnostic companies and other stakeholders" in those countries.
A report from the expert group that carried out the analysis on the WHO TB website (www.who.int/tb) shows that most of the 18 known manufacturers are based in advanced economies, although the test kits are also made in China, India and Singapore.
Most including those based in the United States, Britain, France, Germany, Italy, Japan and the Netherlands are small, privately-owned companies in the medical diagnostic sector, the WHO report indicated.
One listed company, Omega Diagnostics based in Scotland, said the test-kits accounted for less than 2 per cent of its revenues and it would wait for feedback on the WHO statement from its customers before deciding how to proceed.
"We will take it on a case by case basis. I think just a mass withdrawal probably wouldn`t be the way to go but we will respond to our customers` particular market requirements," Omega group sales and marketing director Jag Grewal said.
Grewal said there was "a fair degree of acceptance of this test," adding that "it is being used today in the context that no test is perfect."