Updated: March 13, 2020
Since March 2, the San Francisco Department of Public Health’s Public Health Laboratory (SFPHL) has been conducting COVID-19 tests with kits provided by the Centers for Disease Control (CDC).
Public health laboratories play an important role in the protection of public health in the nation. For new communicable diseases, like COVID-19, they represent the first line of defense and are the locations where newly developed CDC tests are first deployed to protect public health.
While they are usually among the first, public health laboratories do not have the capacity to serve as the sole test center for the entire population and therefore must always prioritize their testing resources. Commercial and health system clinical laboratories are necessary to greatly expand testing to the overall population.
COVID-19 testing options for the public
Commercial and clinical laboratory COVID-19 testing options are currently available to the public upon clinician referral.
The CDC is encouraging clinicians to use their judgment to determine if a patient has signs and symptoms compatible with COVID-19 and whether they should be tested.
Commercial and clinical labs are required to report positive COVID-19 test results to SFDPH.
How many COVID-19 tests can be done at the SFPHL? How are they being prioritized?
Since March 2, the SFPHL has been operating 7 days a week and has the capacity to run several dozen COVID-19 tests each day.
Some key factors that determine the SFPHL testing capacity are the equipment and amount of testing material on hand provided by the CDC.
Due to limited testing capacity, we continue to prioritize COVID-19 testing resources for hospitalized patients and vulnerable, at-risk populations. This strategy will improve the health outcomes of individuals with a higher risk of becoming seriously ill with COVID-19. Here's the guidance for clinicians.
Given the national and statewide concern around the availability of testing resources, SFDPH has been regularly communicating with other state public health laboratories, the California Department of Public Health (CDPH) and CDC.
How many COVID-19 tests have been completed?
From a public health emergency perspective, our priority is positive COVID-19 test results in order to inform our actions. We are only reporting positive COVID-19 cases on the SFDPH website.
COVID-19 tests are being conducted in commercial and clinical labs, and at public health laboratories throughout the region and state.
The California Department of Public Health has the total number of COVID-19 tests across the state.
SFDPH is not independently tracking or reporting on the number of negative test cases from San Francisco commercial and clinical labs. However, commercial and clinical labs are required to report positive COVID-19 test results to county public health agencies.
How long do COVID-19 tests take?
It takes 1 to 2 days to get test results. We are conducting COVID-19 tests 7 days-a-week.
This rapid turnaround time is a great public benefit and allows the City to respond more quickly. Prior to March 2 when SFPHL started COVID-19 testing, tests took 4 to 7 days because all tests needed to be shipped to the CDC labs in Atlanta.
Can you describe the laboratory testing process in simple terms?
- A sealed specimen vial(s) containing two samples (both an oral and nasal swab) arrives at a testing laboratory.
- The samples in the vial is mixed with different chemicals and enzymes designed to isolate any genetic material (RNA) from the virus that causes the human illness COVID-19; this virus is called SARS-CoV-2.
- Using a Polymerase Chain Reaction assay technique, a specialized machine detects if there are SARS-CoV-2 genetic sequences present. Detecting SARS-CoV-2 genetic sequences indicates a positive test result and the patient can be diagnosed with COVID-19. Not detecting these will indicate that there is no presence of SARS-CoV-2 in the test and thus the patient is deemed NOT to have COVID-19.
Can I visit the San Francisco Public Health Laboratory?
No. Due to health, safety, and operational concerns, the SFPHL is not open or being made available to the public or media.
For the media’s convenience, we are providing downloadable b-roll and photos of SFDPH laboratory technicians conducting the COVID-19 test and of a CDC COVID-19 testing kit.