How will the new Beckman Coulter
test be used in the fight against COVID-19?
The purpose of the Access SARS-CoV-2 IgG assay
is to determine if a patient was exposed to COVID-19 and has potentially
developed an immune reaction to SARS-CoV-2.
The recommended method to diagnose a COVID-19
infection is a molecular diagnostic PCR test based on the detection of the
virus RNA,
Antibody assays play a critical role in:
1- Tracking the spread of the
virus
2- Identifying individuals that
have recovered from COVID-19 infection
3- Potentially identifying
individuals no longer susceptible to the virus who can return to work
4- Identifying individuals who
may donate a part of their blood called convalescent plasma, which may serve as
a possible treatment for those seriously ill
5- Identifying those who require
a vaccine once available.
There are a lot of rapid tests in the market right now. How
are these tests different from the one Beckman Coulter is going to produce?
There are a lot of rapid tests in the market right
now.
How are these tests different from the
one Beckman Coulter is going to produce?
Diagnostic and serology tests are
complementary as one is used in infectious patients—mostly those with symptoms
(diagnostic)—and one is used to determine immune response (antibody, or
serology).
The readily available serology tests are
lateral flow assays. In general, lateral flow assays are qualitative,
single-test assays. Our test will be a high-throughput immunoassay laboratory
test that can be integrated in an automated workflow, regardless of the size of
the laboratory.
How soon
after contracting COVID-19 could this test be used to identify immunity in an
asymptomatic person?
The Access
SARS-CoV-2 IgG assay can be used 14–20 days after the infection.
However,
the time it takes could vary from individual to individual, virus to virus, and
assay to assay.
What is the
potential clinical usage of a serology assay for SARS-CoV-2?
Serology
tests like the Access SARS-CoV-2 IgG assay can detect if an individual has been
exposed to the virus—even if they had no symptoms—and if the individual has
potentially developed an immune response by creating antibodies to the virus.
How
does the Beckman Coulter assay work?
The principle of
the assay is to immobilize the virus antigens using magnetic particles to
capture IgG antibodies in patient samples and reveal them using labeled
anti-IgG antibodies.
Is the test
qualitative or quantitative?
The
Access SARS-CoV-2 IgG assay is designed as a qualitative immunoassay.
What
type of samples can be used?
A serum
or plasma specimen may be used.
With
the Beckman Coulter Access SARS-CoV-2 IgG assay, is any additional maintenance
on the instrument before or after running the assay required? Do I need to
collect and batch samples?
No, the Access
SARS-CoV-2 IgG assay is a random-access assay. No batching and no special
maintenance is necessary.
What
is the difference between a SARS-CoV-2 IgG assay developed with an antigen
target of the nucleocapsid protein in comparison to an assay developed against
the spike protein?
Beckman Coulter in an effort of providing
direct detection of antigens developed specifically to SARS-CoV-2 chose as an
antigen target the proteins of the receptor-binding domain (RBD) of the
coronavirus spike protein S1.
In the study, “Detection of SARS-CoV-2-specific humoral and cellular immunity
in COVID-19 convalescent individuals”1, researchers tested sera from COVID-19
patients who had recently become virus-free, and were discharged from the
hospital. They detected SARS-CoV-2-specific humoral and cellular immune
response – specifically they saw antibodies specific to the receptor-binding
domain of the coronavirus spike protein (S-RBD) indicating a significant
correlation between neutralizing antibody titers and anti-S-RBD IgG.
Researchers observed no such correlation with anti-nucleocapsid protein IgG and
concluded that, “Anti-S-RBD IgG might be useful in analyzing serum
neutralization capabilities in COVID-19 patients.”2
Furthermore, researchers noted that S-RBD seemed to induce a greater immune
cell response. This observation suggests that S-RBD may be a promising target
for both serology tests and vaccines to SARS-CoV-2, which could help
individuals build humoral immunity or cellular immunity to this disease.