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COVID-19 | Updates

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Serology

HOW IT WORKS

Serology tests look for the presence of antibodies against a particular pathogen in the patient’s blood. In most cases, a blood sample is spun down to separate out the part of the blood that contains antibodies called serum.

The blood sample is sent to a testing laboratory, where the serum is isolated and prepared for testing. The serum is then mixed with a reagent (test) to determine if antibodies against the virus are present; if so, the reaction between serum and test is measured by a dedicated instrument.

The testing process on the instruments is fully automated, reliable and accurate, providing hundreds of results in a limited amount of time.

Most of the lab-based serology tests for COVID-19 have been designed to detect IgG antibodies against SARS-CoV-2, the long lasting immune response to the virus, or IgM antibodies, the first immune response to the infection. 

WHAT IS IT FOR

IgG serology tests are mainly used to run epidemiological studies among populations to determine the circulation of the virus, whereas IgM serology tests are used to diagnose active infection status.

In particular, the IgG serology tests are used in the following cases:

to help identify the number of individuals in a population who have been exposed to the virus, determining the so-called "seroprevalence", which is the percentage of a population that has been infected with SARS-CoV-2.




to identify individuals who have been previously exposed to SARS-CoV-2 and who may be candidates for donating samples that can be used for convalescent plasma therapy.


In summary, antibody tests show if an individual has been exposed to SARS-CoV-2 at some point in the past, but do not determine when the person was infected or if the infection is still present in the patient.

OVERVIEW




Molecular

HOW IT WORKS

This category of tests works by identifying viral genetic material – the RNA - in a patient’s clinical sample. The common steps of a molecular test for COVID-19 are as follows:

First, a sample is collected from a patient who is suspected of being infected with SARS-CoV-2. This sample is most commonly a nasal or nasopharynx, swab collected from the back of the nasal passage and the upper part of the throat. The swab is then placed in a tube containing a fluid, called transport media, which helps to stabilize the sample prior to testing.

Once the sample arrives at a lab, the usual following step is to extract, or purify out, the virus’ genetic material – the RNA – from everything else that is present in the specimen. Once the viral RNA has been purified, it is ready to be tested.

The most common molecular technique is called PCR, which stands for “polymerase chain reaction”. PCR targets a very small part of the virus’ RNA, and over the course of minutes to hours, amplifies – or copies – that single region of the virus’ genome into potentially tens-of-millions of copies. Enough copies for the PCR instrument to detect – or actually ‘see’: a fluorescent signal is produced each time the virus’ region is replicated.

WHAT IS IT FOR

Molecular tests tell us whether someone currently has a COVID-19 infection.


SYMPTOMATIC INDIVIDUALS

When using a molecular diagnostics test on a patient with symptoms compatible with COVID-19, a positive result allows accurate diagnosis and prompt decisions if the patient is hospitalized. The result can also reinforce the need for the individual to isolate at home for 10 to 14 days.

ASYMPTOMATIC INDIVIDUALS

Molecular diagnostics tests are also used to identify asymptomatic infections; to screen those who don’t have symptoms but who may be infected with SARS-CoV-2 and are therefore a potential source of infection.

OVERVIEW

Antigen

HOW IT WORKS

Antigen tests are designed to detect specific viral proteins. On the surface of the SARS-CoV-2 virus, there are a number of proteins, such as the envelope and spike proteins, which protrude from the viral envelope (the “crown” of the Coronavirus). For Antigen testing the target analyte is the virus “Nucleocapsid protein”, preferred because of its relative abundance. Antigen assays try to determine whether such proteins are present in a patient’s clinical sample, like a nasal swab.     

Scaling up production of antigen tests is quite easy and they are less expensive than molecular diagnostic tests.

A swab is collected from the back of a person’s nose and placed in a small amount of liquid. The fluid is then tested as described for serology tests.

WHAT IS IT FOR

Antigen tests are typically used to diagnose an individual with an active respiratory infection. However, because antigen tests are typically less sensitive than molecular diagnostic tests, we use antigen assays differently. Indeed antigen tests may be negative in a patient with lower amounts of the virus in their collected sample.

The timing of an antigen test is critical. The test should be performed when the virus is present at the highest amount in the individual’s respiratory tract, typically in the first days after the onset of symptoms.

Despite such limitations, rapid antigen tests are a promising new approach to diagnose active SARS-CoV-2 infection, and represent a relevant element in our diagnostic toolbox.

OVERVIEW

TESTSAMPLE TYPESDOWNLOAD PRESS RELEASES

LIAISON® SARS- CoV-2 AG nasal swab
nasopharingeal swab  
LIAISON® SARS- CoV-2 AG: a new high-throughput antigen test for Covid-19 detection in symptomatic patients

DiaSorin's response to COVID-19 outbreak: news flow

MARCH 2020

MOLECULAR TEST

Launch of Simplexa ™ COVID-19 Direct Kit in markets accepting CE Mark and in the U.S. through Emergency Use Authorization (EUA) from the U.S. FDA. A rapid and accurate test to be run on the LIAISON MDX platform to detect COVID-19 in less than 60 minutes. 

APRIL 2020

SEROLOGY TEST  

Launch of LIAISON® SARS-CoV-2 S1/S2 IgG in markets accepting CE Mark and in the U.S. through Emergency Use Authorization (EUA) from the U.S. FDA. A test to be run on the LIAISON® XL platform to identify the presence of antibodies in people who have been infected with SARS-CoV-2.

MAY 2020

SEROLOGY TEST  

LIAISON® SARS-CoV-2 S1/S2 IgG receives approval for the commercialization in Canada, UK and Israel.

JUNE 2020

SEROLOGY TEST  

Launch of LIAISON® SARS-CoV-2 IgM test in markets accepting CE Mark. 
A test to be run on the LIAISON® XL platform to identify the presence of IgM antibodies against SARS-CoV-2.

LIAISON® SARS-CoV-2 S1/S2 IgG receives approval for the commercialization in Brazil.

JULY 2020

MOLECULAR TEST

Launch of Simplexa Flu A/B & RSV Direct Gen II Assay to run with the Simplexa COVID-19 Direct assay in markets accepting the CE Mark.

SEPTEMBER 2020

MOLECULAR TEST

Claim extension to saliva of Simplexa™ COVID-19 Direct assay in markets accepting CE Mark.

Launch of Simplexa Flu A/B & RSV Direct Gen II Assay to run with the Simplexa COVID-19 Direct assay in the U.S.

OCTOBER 2020

SEROLOGY TEST  

Launch of LIAISON® SARS-CoV-2 IgM test in  the U.S.  through Emergency Use Authorization (EUA) from the U.S. FDA. 

ANTIGEN TEST

Launch of LIAISON® SARS-COV-2 AG, a new high-throughput Antigen test to be run on LIASION Family Analyzers in markets accepting CE mark. 

Contact numbers: 

  • From Italy 800016268
  • From other countries +39 0161 1895537