The government approved a new genetic test for the flu virus Tuesday that will allow labs across the country to identify flu strains within four hours instead of four days.

The timesaving test could be crucial if a deadly new strain emerges, federal health officials said. The new test also could help doctors make better treatment decisions during a conventional flu season.

The new test was developed by the Centers for Disease Control and Prevention and Applied Biosystems Inc. of Foster City, Calif. The Food and Drug Administration approved the test kit Tuesday, and state health labs are expected to start using it this fall.

CDC officials celebrated it as a potential lifesaver, especially if the nation is hit by a pandemic of bird flu or some other mutant influenza.

"We'll now be able to detect influenza in the community faster, which allows us to take steps more quickly to protect and save lives," CDC director Dr. Julie Gerberding said in a prepared statement.

The CDC is requiring labs to buy Applied Biosystems equipment to run the test, and the CDC will provide the necessary chemicals. About 20 to 30 state labs should be up and running by the end of the year, CDC officials said.

Until now, the tests used by different states varied. "Now we have all the states able to do this rapid method," said Pete Shult, who oversees infectious disease testing at Wisconsin's state laboratory.

"It's good to use the same method so the results will translate from state to state, and CDC can better understand what's happening," he added.

Six state labs evaluated the new test and found it to be as good as the "gold standard" traditional viral culture method, said Shult, who was involved in that review.

The test correctly detected the most common flu viruses about 99 percent of the time. It also picked up some viruses that the older test missed. Continued...