Immune Response to COVID-19
Coronaviruses, such as SARS-CoV-2 which is responsible for COVID-19 disease, are composed of single stranded RNA and several protein antigens including the spike (S), envelope (E), membrane (M) and nucleocapsid (N) proteins.1 These proteins are antigenic and can trigger a humoral immunologic response during infection.2
When a person is exposed to SARS –CoV-2, the virus may be able to gain entry into the body—usually by entrance through the upper airway and then the lungs. Infection may follow and can be at first asymptomatic followed, in a proportion of cases, by active disease often in the form of upper or lower respiratory tract involvement (fever, coughing, shortness of breath).3
As the COVID-19 infection progresses during asymptomatic and symptomatic phases, the host will mount an immunologic response to various viral proteins by the formation of antibodies which act to antagonize and reverse infection.3
Several types of immunoglobulins (Ig) are created at different times during the body’s immune response. COVIANT™ tests for the IgG antibody, which is detectable approximately 10-14 days after exposure to the antigen or infectious agent. Antibody levels persist in the blood for many months, and it is generally thought that high levels of IgG indicate that a person has been exposed to the infectious agent that triggered the immune response.2,4
Variation of the Levels of SARs-CoV-2 RNA Antigen and IgG After Infection5
COVIANT™ is a qualitative test for the detection of IgG antibodies against SARS-CoV-2 in human plasma and serum. It is intended for use as an aid in identifying individuals with an adaptive immune response to SARS-CoV-2, indicating recent or prior infection.5
This testing has not been reviewed by the FDA but its availability and performance has been determined to be appropriate with Emergency Use Authorization approval granted to the kit manufacturer, EUROIMMUN US, Mountain Lakes, NJ.5
A negative result at one time point can be followed by seroconversion at a later time and is why there is a recommendation to consider repeat testing.4
Our understanding of the COVID-19 disease is evolving and not yet fully achieved. This understanding also applies to the biology and clinical significance of antibody formation and function. Test results should not be the only basis for clinical decision-making. Also, please note that patients with lowered immunity are especially susceptible to SARS-CoV-2 (COVID-19) infection and may exhibit low or no antibody responsiveness.
- Negative results do not preclude SARS-CoV-2 infection and should not be used as the sole basis for patient management decisions
- The sensitivity of the test early after infection is unknown
- A negative result can occur if the quantity of antibodies for the SARS-CoV-2 virus present in the specimen is below the detection limit of the assay
- False positive results for IgG antibodies may occur due to cross-reactivity from pre-existing antibodies or other possible causes
- It is not known at this time if the presence of antibodies to SARS-CoV-2 confers immunity to reinfection
- For in vitro diagnostic use under emergency use authorization only. Interpace Diagnostics is certified under the Clinical Laboratory Improvement Amendments of 1988 (CLIA), 42 U.S.C. §263a, to perform high complexity tests
How to Order
- Full instructions, specimen collection/transport kits and test requisitions are available and ordered through Client Services:
- Phone: (800) 495-9885 or (412) 224-6900
- Email: firstname.lastname@example.org
- Bulk order requisitions (specimen manifest) to facilitate higher volume institutions and single patient requisitions are both available
- EHR/EMR system integration of the specimen manifest and reporting is supported
- Each COVIANT™ shipping kit contains 15 collection tubes
- All 15 collection tubes do not need to be returned at the same time
- Specimens must be refrigerated (2-8°C) until shipping
- Interpace Diagnostics provides vials for use within their specimen collection and transport kits
- Payment is on a direct bill/client bill basis and a Laboratory Services Agreement is required
- Cell-free EDTA plasma (lavender cap) is the preferred specimen type. Cell-free serum (red or gold cap) can also be accommodated for testing
- A minimum of 2 mL cell-free EDTA plasma or 1 mL cell-free serum is needed to run the assay
- Samples should be shipped for overnight delivery using the FedEx® label provided
Turnaround time is expected to be less than 3 days
- Cui J, Li F, Shi ZL. Origin and evolution of pathogenic coronaviruses. Nat Rev Microbiol. 2019;17(3):181-192.
- Guo L, Ren L, et al. Profiling early humoral
response to diagnose novel coronavirus disease (COVID-19). [epub ahead of print, 2020]. Clin Infect Dis. doi:10.1093/cid/ciaa310.
- He F, Deng Y, et al. Coronavirus disease 2019: What we know? [epub ahead of print, 2020]. J Med Virol. doi: 10.1002/jmv.25766.
- Long QX, Liu BZ, et al. Antibody responses to SARS-CoV-2 in patients with COVID-19. [epub ahead of print, 2020]. Nat Med. doi: 10.1038/s41591-020-0897-1.
- Data on file.