UCSF has opened a lab in San Francisco that can process thousands of coronavirus diagnostic tests from all nine Bay Area counties’ public health departments for free — significantly increasing the Bay Area’s testing capacity at a time the state is working aggressively to get more residents tested and obtain test results faster.

UCSF created the lab in Mission Bay over eight days in March, after Gov. Gavin Newsom signed an executive order March 12 that loosened restrictions on clinical labs. It is dedicated solely to processing COVID-19 tests, can run up to 2,600 samples a day and report results in as fast as 24 hours.

UCSF’s main clinical lab has also been running coronavirus tests since March 9, but along with many other types of lab tests. The new lab began processing tests March 20, but only recently added enough staff and lab instruments to be able to process a large number of tests.

If used efficiently, the lab could give California a much needed boost in testing capacity.

In addition to shortages in test components like swabs and chemical reagents, the biggest problems in testing in California have either been that the scale is small — a Menlo Park lab that processes samples from a Hayward testing site, for instance, runs about 100 tests a day — or tests are being sent to commercial labs like Quest that take up to 12 days to report results. Such a lag time makes it difficult for doctors to make a prompt diagnosis and treatment plan and impossible for public health officials to understand the spread of the virus in real time.

Labs across the state process an average of around 9,500 tests a day, according to a Chronicle analysis of daily testing figures released by the state since March 19, when the first figures were released. Daily testing, though, has varied dramatically, from 200 tests a day to nearly 32,000 tests a day. Newsom said Tuesday he hopes the state will test 25,000 people a day within the next few weeks.

The UCSF lab cost about $4 million to set up and run for the next several months, and it is being financed by the Chan Zuckerberg Initiative, the philanthropic organization backed by Facebook CEO Mark Zuckerberg and his wife, Dr. Priscilla Chan. UCSF laboratory medicine specialists Charles Chiu and Steve Miller, both doctors, are overseeing the operation. Staffing the lab are personnel from Chan Zuckerberg Biohub, a research organization that connects scientists at UCSF, Stanford and UC Berkeley and provides grants to support their research. Many are graduate students who have shelved their theses to focus full time on COVID-19 testing.

The UCSF announcement comes as other major Bay Area labs running COVID-19 tests are also expanding testing capacity. Stanford, which began testing March 4, can process about 2,000 samples a day — up from 1,000 a few weeks ago — and Kaiser Permanente Northern California can run 1,000 tests per day and is working to ramp that up to 8,000 to 10,000 a day by mid-May.

The UCSF lab is not a testing site, so people should not go to get tested. But it can accept lab samples from Bay Area county public health departments, which collect them from small doctors’ offices, nursing homes and other medical facilities. So local health officials who previously may have had to wait several days to get results can now get results from UCSF within 24 hours, said Dr. Joe DeRisi, co-president of Chan Zuckerberg Biohub and a UCSF biochemistry professor.

And it is free — a distinction from many labs that either bill insurance companies, charge for processing, or are paid for by other sources. The Hayward testing site is funded by $500,000 from the city, with the expectation that the city may be reimbursed by federal or state disaster funds.

“We do not think there should be a cost barrier to getting tested,” DeRisi said. “This expansion lab really is dedicated to providing Bay Area community service at no charge.”

California ranks 43rd among 50 states and the District of Columbia in testing per capita, according to a Vox analysis of state testing data. The state also has a far larger backlog of pending tests than other states that also report pending numbers. At recently as last week, 64% of tests conducted in California were still pending — in part due to a major backlog at Quest.

The backlog shrank significantly over the weekend, Newsom said, and by Monday had fallen to 9% of overall tests conducted. But California still has 14,600 pending tests, which is far more than any other state that shares data on pending tests. The next is Florida, with about 1,400, about 1% of total tests conducted, according to the Covid Tracking Project.

Catherine Ho is a San Francisco Chronicle staff writer. Email: cho@sfchronicle.com Twitter: @Cat_Ho