Federal Guidelines for Human Bird Flu Test Issued

Federal guidelines rushed out Friday should help companies develop new tests capable of quickly singling out bird flu in infected humans, the Food and Drug Administration said.

The availability of rapid and accurate tests capable of pinpointing bird flu would serve as a vital tool in checking any outbreak of the disease should it jump to humans.

Current rapid tests that use specimens collected from humans weren't designed or intended to detect the H5N1 strain responsible for bird flu, the FDA said. Nor can they distinguish among the various influenza A subtypes, some of which are rarely lethal.

The FDA hurriedly released the guidelines "because prior public participation is not feasible given the national and global public health threat of pandemic influenza," the agency said. The guidelines are in immediate effect but are still subject to public comment. They spell out the steps companies have to follow to ensure the safe and effective use of in vitro diagnostic tests capable of detecting bird flu.

The H5N1 subtype responsible for bird flu is primarily a bird disease for now, although at least 108 people worldwide have died since 2003 after becoming infected with the strain of the influenza virus. Health officials worry the flu strain could mutate into a form easily passed from human to human, sparking a global pandemic.

For the past two decades, it has been two other influenza A subtypes that have primarily caused seasonal flu in humans. FDA officials worry existing tests for those seasonal strains might not be able to pick up newer subtypes, like H5N1, in samples from patients. For that reason, they also recommend manufacturers add warning labels to older tests, including an advisory that the results may need to be confirmed by further testing.