Antibodies developed by the body in response to a viral infection may provide potential immunity against future infection. According to the U.S. Food and Drug Administration, COVID-19 antibody testing may indicate that "the person has been exposed to the virus and developed antibodies against it, which may mean that person has at least some immunity to the coronavirus." Antibody testing uses blood serum specimens and is sometimes referred to as serology testing.
The new Quest Diagnostics antibody service uses tests developed for high-throughput lab environments. Initially, Quest is providing the service based on tests from Abbott and EUROIMMUN, a PerkinElmer company. Quest Diagnostics has completed independent validation studies on both tests. Both tests aid in detecting the presence of immunoglobulin class G (IgG). IgG antibody response typically develops by 14 days after symptom onset. In addition, Quest also continues to pursue other platforms that could enable it to increase testing capacity further.
The Abbott and EUROIMMUN tests are marketed under FDA's Policy for Diagnostic Tests for Coronavirus Disease-2019. Abbott plans to submit for FDA Emergency Use Authorization (EUA) and EUROIMMUN is currently seeking EUA. Test results should be interpreted in connection with other factors, such as symptoms and history. Results signify that antibodies are present, but protective immunity based on these results has yet to be established in clinical trials. Antibody tests by themselves are of limited value in the immediate diagnosis of a patient where COVID-19 infection is suspected.
"As the FDA has indicated, antibody testing has the potential to help healthcare professionals identify people who have been exposed to COVID-19 and who have developed an immune response," said Jay G. Wohlgemuth, M.D., Senior Vice President and Chief Medical Officer for Quest Diagnostics. "In addition, FDA has indicated that antibody testing can help identify those who could contribute a part of their blood, called convalescent plasma, which may provide an avenue for possible treatment for those who are seriously ill from the coronavirus."
Quest expects to scale up testing over the coming weeks. Laboratory capacity is expected to expand from approximately 70,000 tests per day by the end of this week to approximately 150,000 tests a day by early-May. Quest expects to report antibody test results within 1-2 days from specimen collection, depending on demand. Quest will perform the testing in more than 20 Quest Diagnostics laboratories across the United States.
Specimen collection for antibody testing (but not molecular diagnostic testing) at Quest Patient Service Centers
Quest Diagnostics operates approximately 2,200 patient service centers across the United States. These centers are now performing blood draws for COVID-19 antibody testing consistent with health and safety guidelines from the Centers for Disease Control and Prevention (CDC). Test collection is available only to patients who: have a test requisition from a healthcare provider; are asymptomatic; have been asymptomatic for at least 10 days; lack a fever (as assessed by non-contact thermometer checks at time of visit); and are wearing a face mask.
Appointments for antibody testing should be scheduled ahead of time through the Quest Diagnostics MyQuest patient portal or at www.QuestDiagnostics.com. Healthcare providers can also collect blood specimens in their offices for patients for testing by Quest Diagnostics.
Patients suspected of having or confirmed to have active COVID-19 infection or disease may not visit Quest patient service centers, which are not equipped to collect the necessary respiratory specimens for molecular COVID-19 diagnostic testing. Patients who believe they may have COVID-19 are strongly encouraged to contact their healthcare provider.
About COVID-19 testing at Quest Diagnostics
Quest Diagnostics is the leader in infectious disease testing services, with a broad menu of molecular, antibody, and other test services to aid diagnosis, treatment and monitoring. On March 9, 2020, the company introduced an RT-PCR test service to aid the presumptive detection of nucleic acid in respiratory specimens of patients meeting CDC's clinical criteria for COVID-19 testing. RT-PCR tests for COVID-19 are generally used to aid diagnosis during active disease. Quest has performed and reported results of more than 940,000 diagnostic COVID-19 tests. Check our Media Statement for more information and ongoing updates: newsroom.questdiagnostics.com/COVIDTestingUpdates
About Quest Diagnostics
Quest Diagnostics empowers people to take action to improve health outcomes. Derived from the world's largest database of clinical lab results, our diagnostic insights reveal new avenues to identify and treat disease, inspire healthy behaviors and improve health care management. Quest annually serves one in three adult Americans and half the physicians and hospitals in the United States, and our 47,000 employees understand that, in the right hands and with the right context, our diagnostic insights can inspire actions that transform lives. www.QuestDiagnostics.com