Test Screens Blood for Chagas' Disease

It is the first such test approved by the U.S. Food and Drug Administration (FDA).

The developer of the test, Ortho-Clinical Diagnostics (Raritan, HJ, USA), announced that the FDA has licensed the test to screen U.S. blood donations for exposure to Chagas' disease, a tropical, parasitic disease that originates in South America. The test is an enzyme-linked immunosorbant assay (ELISA) called Trypanosoma cruzi.

"Data reported over the past decade indicate a strong upward trend in the proportion of U.S. blood donors testing positive for exposure to the parasite that can cause Chagas' disease,” said Michael Waller, M.D., vice president, clinical and medical affairs, Ortho-Clinical Diagnostics. A study conducted in the same geographic area of the United States documented ratios of Chagas-seropositive blood donors ranging from one positive in 9,900 in 1996, to one in 7,200 in 1997, and to one in 5,400 in 1998. A new study, completed in November 2006, documents the ratio of Chagas-seropositive blood donors as approximately one in 2,000.

The U.S. Centers for Disease Control and Prevention (CDC) estimate that 16 to 18 million people worldwide are infected with Chagas' disease; of those, 50,000 will die each year. Chagas' disease can be treated successfully if detected soon after the infection occurs, but there is no cure once the disease has entered the chronic stage.

In clinical trials, the T. cruzi ELISA demonstrated 100% sensitivity to all geographic strains tested of Chagas' disease and demonstrated an observed specificity of 99.99%. The test qualitatively detects T. cruzi antibody in human serum and plasma. The test is fully automated on the Ortho Summit system.

In 2007, Ortho-Clinical Diagnostics plans to seek U.S. Food and Drug Administration approval to expand use of its test for Chagas' disease in tissue and cell transplants (cadaveric testing) and for general diagnostic purposes.



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