County of Sonoma Begins COVID-19 Antibody Testing for Certain Groups Only

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Beginning Saturday, June 6, 2020, the County of Sonoma will test certain individuals for antibodies to the novel coronavirus (COVID-19). Testing will be performed daily at the Public Health Lab in Santa Rosa, with plans for strategically expanding this service at select hospitals and health centers in the county.

The new antibody testing is part of a larger surveillance effort to better understand the spread of the virus. We initially plan to perform approximately 110 antibody tests per day with the goal of testing 3,500 people within the next four weeks as all testing sites become operational. 

Data from the antibody testing will be used to evaluate the County’s efforts to slow the spread of the coronavirus and help inform decisions around re-opening. This testing is not for the general public and is being done for surveillance purposes. 

This first phase of testing will target first responders—paramedics, EMTs, fire fighters, and law enforcement, and individuals who previously tested positive for COVID-19 and have since recovered. 

Those who are in first responder professions are considered high-risk for exposure to the novel coronavirus and thus have a greater likelihood than the general population of having contracted COVID-19 and subsequently developing antibodies. 

This prioritized testing also will be reserved for high-risk groups that include family/household members and close contacts of people who previously tested positive for the virus. 

There is no charge for this test and people may expect to receive their test results within two weeks.

Unlike viral tests that are used to diagnose a current infection, an antibody test detects antibodies that indicate a previous viral infection. The antibody test does not check for the presence of the virus itself. Rather, it reveals if the immune system has responded to the infection. Depending on when someone was infected and the timing of the test, the test may not find antibodies in someone with a current COVID-19 infection because it can take one to three weeks after infection for antibodies to be detected. 

The antibody tests processed at the Sonoma County Public Health lab require a blood draw from a vein. The test has a high-degree of accuracy meaning that nearly 90% of those who test positive for antibodies had COVID-19 and nearly 100% of those who test negative did not have the virus.

Antibodies consist of proteins that typically help fight off infections, but we do not know yet if having antibodies to the coronavirus can protect someone from getting infected with the virus again, or how long that protection might last. 

Sonoma County Department of Health Services (DHS) will contact residents who have recovered from COVID-19 and their close contacts to schedule an antibody test. We will provide additional details to the public as additional testing sites and increased appointment capacity become available. 

For more information about the antibody testing, viral testing, available County services, or updates regarding the public health emergency, please visit www.SoCoEmergency.org. Residents may also call  2-1-1 or text their zip code to 898-211 in order to text with a 2-1-1 operator. Additional updates are available on County of Sonoma (@countyofsonoma) social media.