COVID-19 infection that is symptomatic or asymptomatic due to exposure to SARS-COV-2, the virus responsible for this infection, can result in IgG antibodies to viral proteins. IgG antibodies to the spike protein or its receptor-binding domain (RBD) which contains sequences unique to the SARS-CoV-2 virus are used as evidence of infection or prior exposure. The appearance of these antibodies is also associated with neutralizing activity. Neutralizing activity attenuates the virus before it can enter cells and cause further damage and protects those who have had a prior infection from re-infection.
COVID-19 antibody testing can be used to assess whether there was prior exposure to the SARS-CoV-2 virus.
COVID-19 antibody testing detects the presence or absence of IgG antibodies to the spike protein of SARS-CoV-2 and its receptor-binding domain.
Knowledge of antibodies to SARS-CoV-2 can be used to assess whether there was prior exposure to the virus. Whether these antibodies confer long-term protection against reinfection is not known.
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Assay Category |
Lab-developed test, antigen-specific T-cell function. |
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Intended Use |
To measure antibody-mediated immunity to the SARS-CoV-2 virus. |
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Methodology |
ELISA-based serologic testing. |
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Test Report |
Available within 2 days of receiving a blood sample. |
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Test Readout |
Optical Density at 490 nm (OD490). |
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Reference Range |
OD490 less than 0.45 and OD490 0.45 and greater. |
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Test Interpretation |
OD490 of 0.45 or less = Antibody-negative. OD490 of 0.45 or greater = Antibody-positive. |
Disclaimer: The test is performed for samples collected at Plexision by the Center for Cellular Therapy at the Medical University of South Carolina, Charleston, SC. This laboratory is the primary laboratory that performs this test. The test only detects IgG antibodies against SARS-CoV-2, not for any other viruses or pathogens.
Purpose
Knowledge of antibodies to SARS-CoV-2 can be used to assess whether an individual has experienced a COVID-19 infection. Whether these antibodies confer long-term protection against reinfection is unknown.
Rationale
Antibodies which develop after viral infections have long been considered a marker of immunity or protection against repeat infection. This protective effect requires that antibodies neutralize the virus. Neutralizing antibodies requires specialized methods to detect such a functional effect on the virus. Detection of IgG antibodies to the virus by simpler methods is a reasonable substitute to estimate immunity following infection because it is associated with neutralizing activity toward the virus. Whether these antibodies confer long-term protection against reinfection is not fully known.
Intended Use
To detect IgG antibodies to the SARS-CoV-2 virus. The presence of antibodies indicates prior COVID-19 infection.
Procedure
The COVID-19 antibody test measures IgG to the spike and RBD proteins of the SARS-CoV-2 virus using an ELISA procedure.
- A whole blood sample, 2 mL from children and 5 mL from adults in red top tubes, is shipped at ambient temperature overnight to Plexision’s reference laboratory.
- IgG to SARS2 viral proteins is detected with ELISA-based serologic testing.
- Results are reported within 48 hours after blood samples reach the laboratory.
- Results are reported as Antibody-negative or Antibody-positive. This interpretation is based on the optical density readout at 490nM (OD490).
- An OD490 greater than 0.45 is seen when antibodies is present. An OD490 of 0.45 or less is seen when antibodies are absent.
Performance
- Sensitivity and specificity for detection of IgG to the spike protein of SARS-CoV-2 was 100% (95% CI 87.1%-100%).
- Sensitivity and specificity for detection of IgG antibody to the RBD protein of SARS-CoV-2 was 88.5% (95% CI 71%-96%).
- These data were generated by testing 148 samples, of which 26 were known positive and the remainder were known negative.
Benefits
- Knowledge about antibodies to SARS-CoV-2 can be used to assess whether the individual has had COVID-19 infection. This exposure may be ‘silent’ because no symptoms were noted by the patient.
- The presence of antibodies is traditionally associated with protection against reinfection of the virus.
- Whether these antibodies confer long-term protection against reinfection is not fully known.
Samples & Handling
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Sample Type |
A whole blood sample is collected in a red-top tube. |
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Volume |
3 mL in children and 5mL in adults. |
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Transport conditions |
Ship priority overnight, at room temperature. The sample must get to Plexision within 30 hours of the phlebotomy. |
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Specimen Stability |
30 hours at room temperature from the time of the phlebotomy. |
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Sample Discard Criteria |
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How to Order
For samples obtained within 10 days of diagnosis of COVID-19 infection, please review CDC guidelines at www.cdc.gov “Interim Guidelines for Collecting, Handling, and Testing Clinical Specimens from Persons for Coronavirus Disease 2019 (COVID-19)”.
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Test Brochure | Contact us for more info. |
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Ordering Tests |
Please complete this form, print, and fax it to 412-224-2776. |
The COVID-19 antibody test determines whether antibodies to the SARS-CoV-2 virus are present. Antibodies develop in individuals who have or have had a COVID-19 infection.
Antibodies to most viruses confirm infection and subsequent protection against reinfection. In the few months-old COVID-19 pandemic, detectable antibody for the SARS-COV-2 virus has been associated with neutralizing effect on the virus. Neutralization of the virus prevents it from infecting cells. Thus, this test can benefit individuals interested in knowing whether they have or have had a COVID-19 infection and as a result may have some protection against reinfection. Whether these antibodies persist for a long period of time and whether the neutralizing effect associated with these antibodies also lasts as long as antibodies are detected is not known.
The COVID-19 antibody test can be ordered by your healthcare provider or physicians at Plexision who can review this test with you. The test requires half to one teaspoon of a blood sample. This sample is shipped overnight to Plexision’s laboratory for analysis. Results are sent to your healthcare provider within 48 hours or two days of your sample arriving at the laboratory. Your healthcare provider will help you understand your results.
Results are ready 48 hours after the laboratory receives the blood sample.
Antibodies to any virus is a measure of prior exposure and protection against reinfection. In the few months-old COVID-19 pandemic, detectable antibody for the SARS-COV-2 virus has been associated with a neutralizing effect on the virus. Neutralization of the virus prevents it from infecting cells.
A negative test confirms that the individual has not had a COVID-19 infection. A positive test confirms that the individual has or has had a COVID-19 infection.
When combined with other clinical and laboratory information, the results of this test can allow your healthcare provider to help you understand whether you have or have had COVID-19 infection.
A negative test confirms that the individual has not had a COVID-19 infection. A positive test confirms that the individual has or has had COVID-19 infection.
When combined with other clinical and laboratory information, the results of this test can allow your healthcare provider to assess whether you have or have had COVID-19 infection.
The COVID-19 antibody test must be ordered by your healthcare provider. The test requisition form is provided here. The completed form can be faxed to 412-224-2776. If there are any questions, please contact (855) PLE.XISION (753.9474) or 412-224-2504.
Your insurance is responsible for payment for this test. Plexision’s patient assistance plans will assist with the cost of the COVID-19 antibody test if there is no insurance coverage.
- Nature Medicine volume 26, pages1200–1204(2020) PMID: 32555424
- N Engl J Med. 2020 Jul 21. PMID: 32706954.
- Curr Protoc Microbiol. 2020 Jun;57(1):e100. PMID: 32302069.
The COVID-19 antibody test is performed for Plexision by the not FDA-approved