Clinical laboratories and some of their medical partners are providing antibody testing for the novel coronavirus, which could provide an improved understanding of how widespread COVID-19 is in Santa Barbara County.
Zugan Health Urgent Care announced in late April that it would offer COVID-19 IgG antibody testing.
Performed by Quest Diagnostics, the test is designed for people who are interested in evaluating their past exposure to COVID-19, according to the Santa Barbara-based urgent care center.
The test will indicate only if people have been exposed to COVID-19 and have developed antibodies, Zugan Health Urgent Care said in an email April 23.
“Quest Diagnostics is recommending tested individuals are symptom-free, and not taking any medicine for COVID-19 related symptoms, for at least 10 days before being tested,” the email said. “After an eligible person is tested, Quest Diagnostics is estimating a three day turnaround time.”
Antibody testing is not recommended for anyone in particular at this time, Santa Barbara County Public Health Department spokeswoman Jackie Ruiz said.
“If people are interested in this option, they should discuss it with their own health care provider,” Ruiz said in an email.
These tests are not diagnostic and can result in false negatives depending on how far out someone is from their initial illness, Ruiz explained.
At this point, it’s unclear if someone will be protected from being infected again if they have antibodies to the virus.
In a recent interview, Dr. David Fisk of Cottage Health told Noozhawk that it’s unknown what kind of immunity people with antibodies have or for how long. Fisk is the head of Cottage Health’s infectious control and prevention, and works as an infectious diseases physician there and at Sansum Clinic.
“We’ve also moved ahead at Cottage with a cautious interpretation of the role for these serologies, because they can be falsely negative and positive so the accuracy of them is limited, and the use in our care of patients and counseling our patients is limited,” Fisk said. “We also don’t even know if you have a positive (result) how much protection you have from re-infection in the future.
“If there is a positive serology in other diseases there can be long-lasting or lifelong immunity in some cases, but we don’t know where that is with COVID-19 yet,” he continued. “We might find that a positive serology means very little.”
At the county Public Health Department briefing April 27, Public Health Officer Dr. Henning Ansorg said Marian Regional Medical Center in Santa Maria can run antibody blood tests in its own laboratory and the commercial facilities, such as LabCorp and Quest Diagnostics.
Those tests are not diagnostic tests for the COVID-19, and people still have to use the nasal swab to test for the virus.
The antibody test is positive when someone has recovered from the infection, and it takes anywhere from two to four weeks for those antibodies to show up in blood tests.
Ansorg said it will be interesting in the coming weeks to see how many people have come in contact with the virus and how far it has spread in the community.
“It’s not a diagnostic test, so it’s more of a surveillance test to find out how many people did come in contact with this virus unknowingly,” Ansorg said.
Results from serologic tests should not be used as the basis to diagnose or exclude COVID-19 (also known as SARS-CoV-2, or severe acute respiratory syndrome coronavirus 2) infection, or to inform infection status, public health officials told Santa Barbara County providers in late April.
“At the current time, health care providers should report any serology test results (positive and negative) to Santa Barbara County Public Health Department via CalREDIE (California Reportable Disease Information Exchange),” the April 27 statement said. “Laboratories should report only the results from serologic tests that have an FDA emergency use authorization.”
The SARS-CoV-2 serology testing statement added, “There is limited information on whether the presence of SARS-CoV-2 specific antibodies can reliably determine if someone is no longer infectious or whether that person is immune to reinfection or how long any immunity may last.”
It continued, “While antibody tests by themselves are of limited value in the immediate diagnosis or screening of individual patients, serology can help us understand the current and past prevalence in the community, how far the pandemic has progressed, and, in the future, may potentially inform strategies for return to work, along with other clinical data.”
According to the Centers for Disease Control and Prevention, antibody blood tests — also called antibody tests — check blood by looking for antibodies, which show if someone had a previous infection with the virus.
But, there are a lot of unknowns.
“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,” the CDC’s website says. “Antibodies are proteins that help fight off infections. Antibody tests should not be used as the only way to diagnose someone as being currently sick with COVID-19.”
On Monday evening, the number of confirmed COVID-19 cases in the county rose by twelve, bringing the total to 526, of which 404 have fully recovered.
Most people who contract COVID-19 exhibit mild or moderate symptoms, according to county public health officials.
— Noozhawk staff writer Brooke Holland can be reached at bholland@noozhawk.com. Follow Noozhawk on Twitter: @noozhawk, @NoozhawkNews and @NoozhawkBiz. Connect with Noozhawk on Facebook.