University of Arizona – State of Arizona COVID-19 Antibody Testing Initiative FAQs

An antibody is a protein made by immune cells that attaches to viruses, bacteria and fungi. There are four broad types of antibodies: IgM, IgG, IgA and IgE. The University of Arizona test measures total antibodies and does not distinguish between these four antibody types.

These types of blood tests detect whether your immune system has made proteins called antibodies. This test is for antibodies that attach to the coronavirus that causes COVID-19.

Nasal swab tests detect the virus itself and indicate active infections. Antibody blood tests check for immune responses against the virus. These antibodies are first made about a week after exposure to the virus. We do not know how long antibodies continue to be produced after COVID19 is cleared, but for other infections, antibodies are continuously made for months or even years after the virus is cleared.

Most people who are infected by the virus make antibodies within a few weeks of infection. However, the amounts of antibodies vary among individuals. Low levels of antibodies might not be detected by this test.

The antibody tests will help us determine who has developed an immune response against the COVID-19 virus.

In the absence of symptoms, it is unlikely for someone to have a positive antibody test and currently be infected.

A positive test result indicates the presence of antibodies. By itself, it does not indicate current infection.

The presence of COVID-19 antibodies means your immune system mounted a response against the virus. We do not yet know the amounts of antibodies that are required to fully prevent subsequent infections, but there might be some level of protection. Because we still do not know enough about this virus, protection should not be assumed.

No. Both tests can detect antibodies and past infection, but there are differences. Finger-prick tests provide rapid YES/NO answers at a clinic or your doctor’s office. However, the accuracy of these tests is highly variable between manufacturers. The University of Arizona test requires a blood draw, and internal validation studies suggest that this test is likely more accurate than most finger prick tests.

The test is an enzyme-linked immunosorbent assay (ELISA). These ELISAs measure antibodies that bind to a part of the coronavirus spike protein called the receptor binding domain. The sensitivity of this assay was determined to be 95.61% and specificity was 100%. Positive and negative predictive values were 100% and 96.24%, respectively.

An Emergency Use Authorization request has been filed with the FDA, and testing is allowed to begin. We anticipate formal FDA Emergency Use Authorization in the coming weeks. In addition, the test was developed in the university’s Clinical Laboratory Improvement Amendments (CLIA)-approved lab, which means the lab has received federal authorization to test human specimens.

Yes, this test will be conducted on the serum, which needs to be separated from the whole blood specimen within 2 hours of collection. Other specification requirements include:

• Container: Red-top (no anticoagulant) or gold-top (serum separator tube; SST) collection tubes.
• Minimum specimen requirement: 1.0 mL of serum from adult patients and 0.5 mL of serum from pediatric patients.
• Transport to laboratory: Serum specimens should be delivered to the UAGC-CS location as soon as possible. If transport is delayed, serums specimens should be refrigerated (2-8 C).
• Unacceptable specimens: Specimens which are severely lipemic and hemolyzed are not acceptable.

Serum separated from whole blood, either by gel/SST or manual transfer, is stable for:

• up to 3 days at room temperature
• up to 1 week when refrigerated at 2 8°C
• up to 6 months when frozen (-20 C or lower)

Diagnosis of COVID-19 is made by detection of SARS-CoV-2 RNA by molecular testing methods, consistent with a patient’s history, clinical observations and epidemiological information.

Qualitative results for the antibody assay are reported as positive, negative or indeterminate.

A positive result may suggest an immune response to a primary infection of SARS-CoV-2, but the relationship between antibody positivity and immunity to SARS-CoV-2 has not yet been firmly established.

Negative or indeterminate results do not rule out SARS-CoV-2 exposure; it usually takes at least 10 days after symptom onset for antibody response to reach detectable levels.

The antibody test results and guidance for interpretation will be directly reported to individuals undergoing the test. Following analysis of all the results, de-identified aggregate data will be made available to the public.

The tests are for health care workers and first responders and are being funded by the State of Arizona. According to their guidance, a health care worker is an individual licensed by any of the following organizations. As testing capacity expands, we anticipate being able to provide tests for additional health care workers licensed by other organizations.

• Arizona Medical Board
• Board of Osteopathic Examiners
• Board of Physician Assistants
• Board of Nursing
• Board of Pharmacy
• Board of Respiratory Care
• Board of Physical Therapy
• Board of Radiologic Technologists
• Dental Board
• Nursing Care Institution

A first responder is any of the following:

• Public Safety Officer
• Firefighter
• EMT

Click on the “Sign-Up Required Here” link. You then will be asked to provide basic information about yourself, complete an online consent process and schedule an appointment using the online tool. You will receive an email confirmation with details about your appointment, including the date, time and directions to the facility.

For the safety of our team members, other participants and our community, individuals with COVID-19 symptoms will not be included in the initial phase of testing. All participants will be screened for symptoms before their appointment, and anyone showing symptoms will not move forward in the process.

In addition to testing sites in Pima County, where the first phase of the initiative began on April 30, new sites will begin opening the week of May 18 in the other 14 counties in Arizona. Overall, there will be 31 antibody testing sites across the state, with additional sites becoming available as needed. The specific testing site for each participant will be selected during the registration process.

Results from tests should be available 3-5 working days after the test. You will receive an email to let you know when your results are available.