Questions about fast flu test

WHO and Hong Kong want to test new Chinese kit for avian flu in their own labs

Dec 13, 2004
Katherine Schlatter(Km_schlatter@yahoo.com)

Chinese scientists announced last week (December 7) that they had developed a new diagnostic kit able to spot avian influenza in hours. But the World Health Organization (WHO) and Hong Kong want to know more about the assay before they put it into use.

"There has been a request for more information," WHO spokeswoman Maria Cheng said when asked about the assays on Friday (December 10). "We're interested in putting these tests through our global influenza network to see how it works in different conditions and to see if everyone gets the same results."

The tests were designed by scientists working at Shantou University and Xiamen University in mainland China and are set for immediate distribution there, where the Center for Disease Control is planning to train workers on its use.

"Other kits developed in the US, like Directgene, can distinguish between Influenza A or B. [This] kit not only tests for influenza A, but also H5 subtype," said Guan Yi at Hong Kong University, one of the collaborating scientists.

Details of the kit's development and design had not been published, Guan Yi said, adding that he was skeptical about whether his collaborating partners want to publish the research. None of the lab-based studies were conducted in Hong Kong, but researchers at the University of Hong Kong are part of the Joint Influenza Research Center that undertook the kit's development.

Guan said the diagnostic kit would not to be used in Hong Kong until the territory's own Centre for Health Protection had conducted trials and was satisfied with the test's sensitivity. "Even though we had H5N1 outbreaks for many years, we were still lacking… a specific monoclonal antibody," Guan said.

In theory the new kit, which takes between 30 and 60 minutes to confirm H5N1, could replace similar diagnostic tests that take days to confirm avian flu. It uses direct and indirect immunofluorescent assays, an enzyme-linked immunosorbent assay, and a colloidal gold-based immunochromatographic dipstick to test for viral antigens and antibodies. Guan Yi says the kit has sensitivity of at least 90%.

Funding for the kit's development came from a foundation established by Li Ka Shing—one of Hong Kong's most successful businessmen. Hong Kong University staff, who usually call press briefings, were caught off guard by the news. The impromptu announcement was made by Zhang Jun of Shantou University.

According to a press release from the foundation, the testing kits can use nasal pharyngeal aspirate, throat swab, virus isolate, and serum for detection or confirmation of the infection: "Within 1 to 2 hours, the suspected human or animal case could be confirmed. These techniques are convenient, rapid, and are easy for non-specialists to use. The kits could be used directly in the outbreak site."