Commercial TB test alert: TDR research leads to an unusual warning from WHO

TDR news item
14 January 2011

The World Health Organization (WHO) will be issuing guidelines recommending against the use of serology tests for tuberculosis because they may be doing more harm than good in high-burden countries, according to The Lancet. This is the first negative recommendation to be made by the WHO. The unusually strong warning is based on more than six years of work by TDR and its partners at the McGill University (Montreal), University of California (San Francisco), the Institute of Tropical Medicine (Antwerp), New York University and the Statens Serum Institut (Copenhagen).

While manufacturers market their tests as filling an important niche in point-of-care tuberculosis diagnostics, in fact, the commercial serology tests, which are sold in scores of countries, are "inaccurate and useless," Madhukar Pai, co-chair of the STOP TB Partnership, told The Lancet.

TDR commissioned two systematic reviews on serological tests that were published in 2007 and also, along with the Institute of Tropical Medicine, Antwerp, conducted a laboratory-based evaluation of 19 rapid serological tests for TB, published in 2008. This evaluation found that none of the assays were of sufficient quality to replace smear microscopy as a diagnostic. Many tests had false results.

In 2010, TDR commissioned an update of the systematic reviews. The findings were identical to the 2007 reviews. TDR and the Stop TB Department at WHO co-convened an Expert Group Meeting to review the findings and discuss the implications for policy.

“The expert group endorsed the findings from an updated systematic review since the TDR report in 2008 and essentially concluded that we should proceed with negative policy guidance based on the fact that the performance characteristics of these tests were way below what one would want and also because the quality of the data were so weak and so bad that it warranted a recommendation against the use of these tests”, Karin Weyer, Stop TB coordinator of diagnostics and laboratory strengthening told The Lancet. “We quickly discovered that manufacturers of these commercial serodiagnostics simply change the name of the test frequently and re-market and re-sell the same test under a new brand name," she said.

At the same time, said Weyer, WHO has approached the negative guidance carefully, so as not to discourage future research and innovation.

For further information contact:

Dr Andy Ramsay