More U.S. Blood Donors Positive for Chagas disease

A new test has been developed to screen blood donations for Chagas disease--a tropical, parasitic disease that originates in South America.

Called the Ortho T.cruzi enzyme-linked immunosorbant assay (ELISA) Test System, it is the first blood-screening test for Chagas disease approved by the U.S. Food and Drug Administration (FDA) for use in the United States. The test is produced by Ortho-Clinical Diagnostics (Raritan, NJ, USA).

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 U.S. documents ratios of Chagas- seropositive blood donors ranging from one positive in 9,900 in 1996, to one in 7,200 in 1997, to one in 5,400 in 1998. A new study, just completed in November [2006], documents the ratio of Chagas-seropositive blood donors at approximately one in 2,000.

Also called American trypanosomiasis, Chagas disease is an infection caused by the blood parasite Trypanosoma cruzi, (T cruzi). Transmission occurs through insect bites, blood transfusions, organ transplants, and via infected pregnant women to children in utero. Chagas disease can damage heart tissue and can cause death. The Centers for Disease Control and Prevention (CDC, Atlanta, GA, USA) estimates 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.

This new test will help prevent transmission of Chagas disease through blood transfusions, said Richard H. Carmona, M.D., M.P.H., FACS, 17th Surgeon General of the United States. This case demonstrates our public health system at its best. The FDA, noticing an increase in the incidence of Chagas disease, called upon the diagnostics industry to develop a reliable blood- screening test for use in blood banks nationwide.

Working together, a remarkable solution is being implemented to safeguard the health and safety of the American people.

In clinical trials, the Ortho T.cruzi ELISA Test System 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, fully automated on the Ortho Summit System, will be used to screen blood donations for the presence of antibodies that develop in response to exposure to the parasite that can cause Chagas disease

The Ortho Summit System fully automates the processing of blood donation screening assays. The automated features of the instruments and compliance-driven software ensure stringent test standards are met and all critical functions are monitored, controlled, and documented to achieve the highest quality standards and safety of the blood supply.



Related Links:
Ortho-Clinical Diagnostics
Centers for Disease Control and Prevention