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The COVID-19 pandemic is caused by the SARS-CoV-2 virus, a new member of the coronavirus group. The virus can cause asymptomatic infection or mild flu-like symptoms. Pneumonia and respiratory failure requiring mechanical ventilation represent more severe illness.

In recent studies, cell-mediated immunity to SARS-COV-2 has been found in healthy individuals who have never been exposed to the virus. Immunity in unexposed individuals may result from prior exposure to human coronaviruses which cause up to 15% of flu-like illness in adults and are similar to SARS-CoV-2. Antibodies to the virus develop after COVID-19 infection. Antibodies may fail to develop in some or may be short-lived in others.

Assessing immunity to SARS-COV-2 is an important goal as lockdown measures are relaxed and people return to school, work, and entertainment. Individuals 60 years or older, those with underlying chronic conditions like diabetes and cardiovascular disease, and immunosuppressed individuals such as those with organ transplants may be especially vulnerable during this period.

PlexCOVID-19 is a lab-developed blood test that measures the level of cellular immunity to SARS-CoV-2. Severe forms of COVID-19 infection may be associated with decreased cell-mediated immunity to SARS-CoV-2.

Knowledge about cell-mediated immunity to SARS-CoV-2 and therefore the risk of COVID-19 infection can be combined with available clinical data to:

  • Assess disease severity in those with COVID-19 infection.
  • Assess infection risk in vulnerable populations.

PlexCOVID-19 measures functional cell-mediated immunity and general T-cell responsiveness to SARS-CoV-2.

PlexCOVID-19 measures functional cell-mediated immunity to SARS-CoV-2. SARS-CoV-2.-specific T-cells, which express the inflammatory marker, CD154 are measured after stimulation with the spike antigen of SARS-CoV-2. Simultaneously, T-cell stimulation with mitogen measures general T-cell responsiveness.

The PlexCOVID-19 test predicts the risk of severe COVID-19 infection among patients diagnosed with COVID-19 infection. The test also predicts the risk of COVID-19 infection in the general population that may or may not have been exposed to the SARS-CoV-2 virus. This risk score is generated by measuring cell-mediated immunity of T-cells and their T-cell subsets, combined with patient attributes such as age and certain underlying conditions.

# CATEGORY DETAILS

1

Assay Category

Lab-developed test, antigen-specific T-cell function.

2

Intended Use

To measure cell-mediated immunity to the SARS-CoV-2 virus.

3

Methodology

Stimulation of peripheral blood leukocytes with the spike protein antigen of SARS-CoV-2 and flow cytometry. Mitogen-stimulation of peripheral blood leukocytes serves as a positive control.

4

Test Report

Available within 30 hours of receiving the blood sample.

5

Test Readout

Frequency (%) of SARS-CoV-2-specific T-cells that express CD154, an inflammatory marker. This readout along with patient variables is entered into an algorithmic calculation that generates a binary risk score of increased or decreased risk.

6

Reference Range

The test reports a risk score indicating an increased or decreased risk of severe disease. This score is generated by combining responses of CD8 T-cells to the SARS-CoV-2 spike protein antigen and patient age.

The test also reports a risk score indicating an increased or decreased risk of COVID-19 infection in unexposed individuals. This score is also generated by combining responses of different types of T-cells to the SARS-CoV-2 spike protein antigen and patient variables.

7

Test Interpretation

Decreased risk of severe infection is associated with an 87% probability that the patient will not require mechanical ventilation with a COVID-19 infection. The probability of mechanical ventilation is 61% with a test that shows increased risk. An increased risk of severe infection has been observed in 85% of patients with COVID-19 infection who required mechanical ventilation for respiratory failure. This knowledge can be combined with other clinical and laboratory tests to make treatment decisions.

The risk of COVID-19 infection is decreased in 81% percent of unexposed individuals and increased in 81% of those with COVID-19 infection. This knowledge can be combined with other clinical and laboratory tests to make determinations about the risk of COVID-19 infection in an individual.

Purpose

Knowledge about cell-mediated immunity to SARS-CoV-2 and therefore the risk of COVID-19 infection can be combined with available clinical data to:

  • Assess disease severity in those with COVID-19 infection.
  • Assess infection risk in vulnerable populations.

Rationale

In its severest form, COVID-19 infection can lead to pneumonia and progress to respiratory failure which requires mechanical ventilation. Persistent pneumonia and respiratory failure can damage the lungs irreversibly and can be fatal. Predisposing factors include unchecked viral infection due to impaired immunity and chronic underlying illnesses such as diabetes, cardiovascular disease, compromised immunity, and lung disease. Knowledge about who might be at risk for severe disease can allow caregivers to use preventive measures and improve outcomes.

Predicting who might be at risk for COVID-19 infection is also essential as more individuals engage in the economy for social and economic reasons. Vulnerable populations at added risk of COVID-19 infection include individuals with chronic underlying conditions and those who must engage extensively with the general public as part of their daily activities and employment.

Cell-mediated immunity offers one way to assess the risk of infection in the general population and the risk of severe disease with COVID-19 infection. Prior exposure to human coronaviruses which have caused flu-like illness since the 1960s has resulted in cell-mediated immunity that is also reactive to the SARS-CoV-2 coronavirus. This virus causes COVID-19 infection. This immunity is impaired at the onset of COVID-19 infection, to the greatest extent in those with severe COVID-19 infection. Therefore, cell-mediated immunity to the SARS-CoV-2 virus can be used to estimate the risk of COVID-19 infection in the general population and assess disease severity in those already infected with COVID-19.

Intended Use

To assess the risk of COVID-19 infection and the severity of this infection.

Procedure

  • PlexCOVID-19 measures functional cell-mediated immunity to the SARS-CoV-2  virus. 
  • A whole blood sample of 3 mL from children and 5 mL from adults. The blood must be in sodium heparin (green-top) tubes. Samples must be shipped at ambient temperature overnight to Plexision’s reference laboratory.
  • SARS-CoV-2-specific T-cells that express the inflammatory marker, CD154, are measured after stimulation with the spike protein antigen of this virus. 
  • Simultaneously, stimulation of these cells with mitogen measures general T-cell responsiveness. 
  • Results are reported within 24 hours after blood samples reach the laboratory.
  • Results are reported as a binary risk score in the form of an increased or decreased risk of severe disease in patients with a COVID-19 infection. Severe disease is associated with respiratory failure requiring mechanical ventilation.
  • A binary risk score indicating increased or decreased risk of COVID-19 infection is also reported in unexposed individuals who are considered vulnerable by virtue of age or certain underlying conditions.

Performance

Risk of SEVERE COVID-19 infection:
  • Decreased risk of severe infection reported by the PlexCOVID-19 test is associated with an 87% probability that the patient will not require mechanical ventilation for respiratory failure with COVID-19 infection. 
  • The probability of respiratory failure is 61% with a test that shows increased risk. An increased risk of severe infection has been observed in 85% of patients with COVID-19 infection who experienced respiratory failure. 
  • This knowledge can be combined with other clinical and laboratory tests to make treatment decisions on a COVID-19 infection.
Risk of COVID-19 infection
  • 81% percent of unexposed individuals show a decreased risk of infection on the PlexCOVID-19 test.  
  • 81% of those with a COVID-19 infection show an increased risk of infection on the PlexCOVID-19 test. 
  • This knowledge can be combined with other clinical and laboratory tests to make determinations about the risk of COVID-19 infection in an individual.

Benefits

  • Predicting who might be at risk for respiratory failure can allow the use of preventive treatment before the disease worsens. Recovery from respiratory failure can have a poor outcome after a COVID-19 infection.
  • Assessing vulnerability to COVID-19 infection can help vulnerable individuals in the general population. Such individuals include those who have not been exposed to the SARS-CoV-2 virus and who have chronic underlying conditions. Others include those with low immunity or who have to engage with the general public as part of their work.

Sample & Shipping

# CATEGORY DETAILS

1

Sample Type

A whole blood sample is collected in a sodium heparin (green-top) tube.

2

Volume

3 mL for children and 5 mL for adults.

3

Transport Conditions

Ship priority overnight, at room temperature. The sample must get to Plexision within 30 hours of the phlebotomy.

4

Specimen Stability

30 hours at room temperature from the time of the phlebotomy.

5

Sample Discard Criteria

  • Transport time more than 30 hours from phlebotomy.
  • Lithium heparin (green-top) tube or ACD (yellow-top) tube.
  • Clotted, hemolyzed, frozen, refrigerated, or broken vacutainer seal.

How to order

# CATEGORY DETAILS

1

Test Brochure Contact us for more info.

2

Ordering Tests

Please complete this form, print, and fax it to 412-224-2776.

PlexCOVID-19 is a blood test that helps your healthcare provider determine your risk of severe COVID-19 infection. The test can also determine the risk of COVID-19 infection if you have not been exposed but may be at increased risk of infection.

Patients with COVID-19 infection can benefit from the knowledge of their risk of severe forms of infection. Determining a severe form of COVID-19 infection can benefit the patient by allowing preventive treatment to be administered in a timely manner.

Unexposed individuals who are vulnerable because of underlying conditions or those individuals who must engage extensively with the general public as part of their daily activity may benefit from knowing their risk of COVID-19 infection.

The PlexCOVID-19 test must be ordered by your healthcare provider. 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 24 hours of your sample arriving at the laboratory. Your healthcare provider will then help you understand the results.

Test results are ready 24 hours after the laboratory receives the blood sample.

The PlexCOVID-19 test measures the level of cell-mediated immunity toward the SARS-CoV-2 coronavirus. This immunity is measured by a type of white blood cell called the T-lymphocyte or T-cell. When combined with patient variables, these measurements can be used to generate a binary risk score. The test is reported as an increased or decreased risk of severe COVID-19 infection for patients with COVID-19 infection. For individuals with no prior exposure to the SARS-CoV-2 virus, the test is reported as an increased or decreased risk of COVID-19 infection.

Decreased risk of severe infection is associated with an 87% probability that you will not require mechanical ventilation with COVID-19 infection. An increased risk of severe infection has been observed in 85% of patients with COVID-19 infection who required mechanical ventilation for respiratory failure. The probability of mechanical ventilation is 61% with a test that shows increased risk. This knowledge can be combined with other clinical and laboratory tests to make treatment decisions.

The risk of COVID-19 infection is decreased in 81% percent of unexposed individuals and increased in 81% of those with COVID-19 infection. This knowledge can be combined with other clinical and laboratory tests to make determinations about the risk of COVID-19 infection in an individual.

  • Knowing the risk of severe infection if you have been diagnosed with COVID-19 infection can allow your physician or provider to use preventive measures to limit progression.
  • Knowing the risk of COVID-19 infection if you have never been exposed, but may be vulnerable due to your employment or lifestyle or because you have other chronic conditions, can help your physician recommend appropriate preventive measures.

The PlexCOVID-19 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.

Plexision will bill your healthcare facility or your insurance plan as indicated on the requisition form. Plexision’s patient assistance plans will assist with the cost of PlexCOVID-19 if there is no insurance coverage.

  1. Braun J, Loyal L, Frentsch M, et al. Presence of SARS-CoV-2 reactive T cells in COVID-19 patients and healthy donors. medRxiv 2020:2020.04.17.20061440.
  2. Grifoni A, Weiskopf D, Ramirez SI, et al. Targets of T Cell Responses to SARS-CoV-2 Coronavirus in Humans with COVID-19 Disease and Unexposed Individuals. Cell 2020;181:1489-501 e15.
  3. Le Bert N, Tan AT, Kunasegaran K, et al. SARS-CoV-2-specific T cell immunity in cases of COVID-19 and SARS, and uninfected controls. Nature 2020.
  4. Sekine T, Perez-Potti A, Rivera-Ballesteros O, et al. Robust T cell immunity in convalescent individuals with asymptomatic or mild COVID-19. bioRxiv 2020:2020.06.29.174888.
  5. Weiskopf D, Schmitz KS, Raadsen MP, et al. Phenotype of SARS-CoV-2-specific T-cells in COVID-19 patients with acute respiratory distress syndrome. medRxiv 2020:2020.04.11.20062349.
  6. Kahn JS, McIntosh K. History and recent advances in coronavirus discovery. Pediatr Infect Dis J 2005;24:S223-7, discussion S6.
  7. Ng K, Faulkner N, Cornish G, et al. Pre-existing and de novo humoral immunity to SARS-CoV-2 in humans. bioRxiv 2020:2020.05.14.095414.
  8. Long QX, Tang XJ, Shi QL, et al. Clinical and immunological assessment of asymptomatic SARS-CoV-2 infections. Nat Med 2020.
  9. Ibarrondo FJ, Fulcher JA, Goodman-Meza D, et al. Rapid Decay of Anti-SARS-CoV-2 Antibodies in Persons with Mild Covid-19. N Engl J Med 2020.
  10. Ashokkumar, C., Rohan, V., Kroemer, A., Almeda, J., Mazariegos, G., Higgs, B., . . . Sindhi, R. K. (2020). Predicting COVID-19 Infection and Its Severity with T-Cell-Mediated Immunity in Immunosuppressed and Non-Immunosuppressed Individuals. SSRN Electronic Journal. doi:10.2139/ssrn.3706759

Patent pending

PlexCOVID-19 is not FDA-approved

About

Plexision develops cellular biomarkers for personalized diagnosis and drug development in solid organ transplantation and immunological disorders. We also pioneer in R&D projects centered on integrating biomarker targets in all phases of drug development, from preclinical to post-marketing. Plexision’s technology can be adapted to

  • - Assess disease risk for several immunological disorders.
  • - Predict the success of a drug for a specific patient.
  • - Develop dosing recommendations for new immunological drugs.

Our state-of-the-art laboratory is CLIA-certified and located in Pittsburgh, PA.

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