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A UC San Francisco lab that analyzes positive coronavirus test results is a big reason behind the quick identification of the Omicron variant in California, the first documented case in the United States.

The lab run by Dr. Charles Chiu, an infectious disease specialist at UC San Francisco, routinely analyzes positive coronavirus cases in San Francisco for their genomic sequence to identify the variant.

Chiu said he first heard about the positive case at 3 p.m. Tuesday. The moderately ill San Francisco resident, who returned home Nov. 22 from a trip to South Africa, became symptomatic on or around Thanksgiving and got tested for the coronavirus on Sunday, and on Monday, the results came back positive from another lab.

Chiu’s lab received a sample of the detected coronavirus by 8 p.m. Tuesday. Scientists ran a fast molecular test, which produced results in two hours that were suggestive, but not conclusive, that the coronavirus that sickened the resident was the Omicron variant.

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