COVID-19 (SARS-CoV-2) Testing

COVID-19 (SARS-CoV-2) Facts:

Coronavirus Facts

• Coronaviruses are the cause of some colds and also can cause more serious diseases such as COVID-19, SARS, and MERS.
• Coronaviruses have unique spike structures on the outside of the virus particle.  These spike proteins allow the virus to enter into specific cells.
• Most coronaviruses are found in animals.
• The genome of the virus is stored in RNA, not DNA.
  

Antibody Tests for COVID-19:

An antibody test detects the presence of antibodies, which are specific proteins made in response to infections.  Antibodies are detected in the blood of people that are tested after an infection.  Antibodies show an immune response to an infection.  Antibody test results are especially important for detecting previous infection in people who had few or no symptoms.

Accurate interpretation of serology testing depends on antigen specificity, but also on the type of antibody being detected.  Humans have five different classes of antibodies, with each playing a unique role in immunity.  IgM, IgG, IgA, and total antibody detection are the primary targets of serology tests for COVID-19.

Antibody test results should not be used to diagnose someone with an active SARS-CoV-2 infection.  It typically takes 1 to 3 weeks after infection with SARS-CoV-2 for antibodies to develop, with some people it may take even longer to develop antibodies.  Depending on when someone was infected with the virus and the timing of when the test was performed, serology tests may not detect antibodies in someone with an active infection. A test that detects the SARs-CoV-2 virus directly in respiratory samples may be used to diagnose active infections.

We do not know if the antibodies that result from SARS-CoV-2 infection will provide an individual with protection (immunity) from being infected again by the virus.  If antibodies are found to provide immunity, it is not known how much antibody will provide protection or how long the protection may last.

-excerpts from the Centers for Disease Control and American Society of Microbiology

• A positive result means it is likely that the patient has or has previously had COVID-19 and the patient has developed antibodies. Healthcare providers will help interpret the results and determine how to best care for the patient.
• A negative result means that antibodies to the SARS-CoV-2 virus were not detected in the sample. It is possible for the test to provide a false negative result in some people with COVID-19, particularly in the early stages of the disease. Healthcare providers will help interpret the results and determine how to best care for the patient. Molecular detection of the virus may be considered to rule out recent or active infection in those individuals.
• A borderline or equivocal result means that the assay can not determine if the patient does or does not have antibodies to the SARS-CoV-2 virus. Retesting in 1 to 2 weeks may result in improved or definitive results. Also, molecular detection of the virus may be considered to rule out recent or active infections in those individuals.
• Results from antibody testing, positive or negative, should not be used as the sole basis to diagnose or exclude SARS-CoV-2 infection.
• Positive results may be due to past or present infections with non-SARS-CoV-2 coronaviruses.
• If you have questions about the interpretation of your test results contact your authorized healthcare provider.
• Tests for SARS-CoV-2 are authorized by by the FDA under an Emergency Use Authorization.

“Simply put, the COVID-19 serology blood test tells you if you have been exposed.  Not all patients that are exposed show symptoms of disease. Serology tests for IgG begin to exhibit positive results on average 14 or more days after infection or exposure to SARS-CoV-2.  Furthermore, tests for IgM and, the more sensitive, IgA antibodies can be useful for detection of exposure earlier than IgG antibodies.  Generally, these antibody tests may exhibit a positive result as early as 4 to 14 days after exposure.  Serology tests are useful in helping healthcare providers assess the risk of spread, in disease surveillance, and for determining risk of exposure.  A positive serology result does not eliminate the possibility of a patient having an existing and active COVID-19 infection.  It is possible, a small number of patients may generate antibodies, become sero-positive, and be in a ‘carrier state’ – able to transmit the virus.  Remember the gold standard test for SARS-CoV-2 infection is PCR tests.  Please see your healthcare professional for advice regarding testing and result interpretation.

Fry Laboratories, LLC has researched the best available serology for test.  These tests are Emergency Use Authorized by the FDA.  It is our commitment to provide the best and most accurate results in a timely manner for our patients and client healthcare providers.”

-Stephen E. Fry, M.D., Founder and Medical Director, Fry Laboratories, LLC, May, 2020