The number of cases they're looking into has doubled since Friday, but so far 26 of the 28 flu specimens they've tested have been negative. The testing process is long and complicated -- each one takes several hours to determine the strain.
"We can test 28 a day, if we test after hours we could double that amount. So that would be 56 a day. I'd say anything over 56 a day would be beyond our search capacity," said Lynn Murrin, a lab director.
Marin health officials have had to bring in extra help to answer the large number of phone calls they're getting.