COVID-19 Antibody Testing:
We are getting many questions regarding antibody testing for COVID-19.
The use of antibody test results is not yet known. There are ongoing concerns about the quality of antibody tests, and how to interpret the results of this testing – for instance, what does it mean to have antibodies? Do they confirm immunity? How should physicians advise patients who are positive or negative? Are persons with antibodies still infectious and require isolation/quarantine? How often would it make sense to test antibodies? These questions have not yet been answered.
What you need to know:
- Antibody testing should not be used alone to diagnose COVID-19
- It is most useful in the following situations: Identification of convalescent plasma donors; epidemiologic studies of disease prevalence in the community, which are being conducted by government and research entities; verification of vaccine response once antibody correlate(s) of protection identified (future use). The use of this test for diagnosis of infection remains unclear.
- At this time, positive antibodies may indicate exposure (assuming, that the positive is a true positive) but does not necessarily indicate immunity. The value of repeat testing without any symptomatic illness is likely very low.
- Currently available serology tests results should NOT be used to guide return to work policies, use of PPE, or “safer at home”practices
- Quest and some other labs currently offer only an IgG antibody test, not IgM, and they also use multiple different assays that have been released for emergency use by the FDA but are not FDA-approved. We do not yet know the sensitivity or specificity of their tests.
- At home and finger prick antibody tests are not considered reliable so they are not recommended at this time.
CHLA is performing blood draw antibody samples for Anti-SARS-CoV-2 Antibody IgG at the CHLA drive through location in addition to the outreach satellite locations in Pasadena and Encino. This service is open to Health Network physicians like us, families, staff and patients. The test they use is considered a very good one.
What patients need to know:
- Antibody testing may indicate, if present, that a person has had the novel coronavirus though it be could be positive due to other coronaviruses like the common cold. It looks for signs of previous infection but does not guarantee that someone had COVID-19.
- Antibody testing cannot be used to predict individual immunity. In other words, we do not know with any certainty that you cannot get COVID-19 again. If there is any immunity, we also don’t know how long the potential immunity could last.
- With this in mind, patients should continue to practice social distancing, wear appropriate face covering, frequent washing of hands with soap and water, and monitoring your own and family’s health for COVID-19 symptoms.
- The antibody test may not be covered by your health insurance and could result in having to pay cash.
For more information, see the Los Angeles County Department of Public Health Antibody Testing FAQ.