July 18, 2011
WHO Warns Against Use Of TB Blood Tests
Blood tests commonly used to detect tuberculosis can be unreliable and potentially dangerous to patients, according to a World Health Organization (WHO) warning issued on Sunday.
According to Frank Jordans of the Associated Press (AP), "The U.N. health agency said it will issue an unprecedented recommendation against using such tests for the infectious lung disease that affects some 14 million people worldwide. As much as a third of the world's population is thought to harbor the bacteria that causes TB."
In fact, Mario Raviglione, the director of the organization's Stop TB bureau, went so far as to call the tests "a waste of money and time" and accusing them of "putting proper care at risk" due to an abundance of false negative and false positive readings, Jordans reported.
Blood tests "are in fact dangerous to patients, since some cases will not be detected and some will be called TB when in fact they do not have it," Raviglione told the AP on Sunday. "Many of these tests are used in the private-for-profit sector, charging poor people who do not understand the lack of value of the test."
The WHO's official ruling on the matter is expected later this week, according to Jordans.
According to Centers for Disease Control and Prevention (CDC) statistics, approximately one-third of the global population are currently infected with TB, an airborne disease that typically affects the lungs but can also affect the brain, kidneys, and spine. Approximately nine million people worldwide contract tuberculosis annually, and the disease--which can be fatal if left untreated--is responsible for more than two million deaths each year.
Four blood tests have been approved for use in the US by the Food and Drug Administration (FDA), according to the CDC, and two of them--the QuantiFERONÃ®-TB Gold In-Tube test and T-SPOTÃ®.TB test--are currently commercially available. However, elsewhere on the organization's website, the CDC notes that "errors in collecting or transporting blood specimens or in running and interpreting the assay can decrease the accuracy" of these tests.
On the Net:
- World Health Organization (WHO)
- Centers for Disease Control and Prevention (CDC)
- Food and Drug Administration (FDA)