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By Lisa Seachrist

Washington Editor

WASHINGTON ¿ The FDA approved the Chiron RIBA 3.0 Strip Immunoblot Assay (SIA) as a confirmatory test for hepatitis C antibodies in human blood.

The test is the product of a joint business between Raritan, N.J-based Ortho-Clinical Diagnostics Inc., a Johnson & Johnson company, and Chiron Corp., of Emeryville, Calif. It is a supplemental test to confirm infection in human plasma specimens that are found to react repeatedly to hepatitis C antibody screening tests. The test will be distributed by Ortho-Clinical Diagnostics.

¿This is a particularly neat contribution because it really allows us to serve the public health,¿ said Rajen Dalal, president of the blood-testing business division at Chiron. ¿This test helps to reduce the indeterminate results by enhanced sensitivity to the core antigen.¿

The test is an improvement over Chiron¿s RIBA 2.0 SIA, which is currently used for testing donor blood for infection with hepatitis C virus (HCV).

It is the most common blood-borne infection in the United States. An estimated 3.9 million people are infected with the virus, with 36,000 new infections each year.

While most people infected with HCV will have no symptoms, infection with the virus does place one at higher risk for chronic liver disease and liver cancer.

In response to the growing problem of HCV infection, the Department of Health and Human Services has instituted a look-back program to identify blood recipients who may have received HCV-infected blood. The program includes notifying prior recipients of blood products from donors who were initially non-reactive to HCV antibodies at the time of donation, but were found to be reactive at a subsequent donation.

Blood banks typically use an ELISA (enzyme-linked immunoabsorbent assay) to screen blood for antibodies to HCV that result from infection with the virus. Should a screen show the presence of HCV antibodies, the blood bank will rescreen with an ELISA assay. After a second positive result, a repeat reactivity, the blood banks then employ a confirmatory test.

Better Sensitivity Means Truer Result

Bruce Phelps, senior director for product development at Chiron, noted that while the RIBA 2.0 SIA provided confirmation of a positive result or proved a negative result for many tested samples, too many samples had ¿indeterminate¿ results.

¿With the RIBA 3.0 SIA, the number of indeterminate results is cut down because the test has an enhanced sensitivity to the core antigen,¿ Phelps said. ¿Now, 85 percent of the indeterminate samples can be resolved with RIBA 3.0.¿

As a result, blood banks can be more confident they are going back to a donor or recipient with reliable information that he has an HCV infection, or has received blood from a person who tested positive for HCV.

Chiron/Ortho-Clinical Diagnostics provide the ELISA test and the confirmatory test to all blood banks run by the American Red Cross, as well as to other blood banks. The RIBA tests are the only FDA-approved supplemental tests for hepatitis C infection.

Chiron¿s stock (NASDAQ:CHIR) closed at $22.937, up $0.625. Johnson and Johnson¿s stock (NYSE:JNJ) closed at $86.625 a share, up $2.00. n