Which test to use and when?ⁱ

Reliable diagnostic tests targeting patients that are currently infected by the virus, as well as those that have an immune response against the virus, are valuable. However, it is important to understand which tests are most suitable to use depending on their intended purpose.

There are two different testing types available for COVID-19: a test for current infection (diagnostic test) and a test for recent or previous infection which is also known as antibody test.

Current Infection – Diagnostic Test

A diagnostic test is used to detect presence of the virus, therefore is indicative of a current infection. This type of test usually involves the assessment of a nasal or throat swab. The technology for diagnostic test includes molecular and antigen method.

  • Molecular tests, also known as RT-PCR (Reverse transcription polymerase chain reaction) test, detects genetic material from the virus. Molecular tests are typically performed in a laboratory setting.
  • Antigen tests detect specific proteins from the virus. Antigen test can be performed on an automated laboratory instrument or as a rapid test which typically requires no laboratory equipment, making the latter well suited for use in any setting.

Recent or Previous Infection – Antibody Test

An antibody test detects the immune response if a person has been recently or previously infected. This test is usually administered through blood draw.

Understanding if a person has recently or previously been infected with SARS-CoV-2 and the level of antibodies in the body is an important next step, and may allow the determination of the effectiveness of vaccines and therapies.

IDS Solutions for Antigen Testing

These tests detect a current infection by identifying SARS-CoV-2 antigens, which are viral surface proteins that cause an immune response.

Antigen tests involve the assessment of a nasal or throat swab which can either be performed in a clinical laboratory, on specific equipment that typically provides the results in hours, or by using a simple, rapid test format, which typically requires no laboratory equipment, providing results within 15 minutes (assay dependent).

Rapid SARS-CoV-2 antigen testing is a simple but useful tool to support swift identification of individuals with current infection, allowing faster deployment of contact tracing measures to help limit the spread of the infection. These tests are simple to use, requiring no specialised training or equipment to run supporting their use in any setting such as near patient, workplace, school, etc.

IDS offers following rapid antigen tests to detect the presence of SARS-CoV-2 Nucleocapsid protein antigen using direct nasopharyngeal (NP) swab. These simple-to-use antigen tests deliver rapid result within 15 minutes, without any laboratory equipment.

IDS Solutions for Antibody Testing 

Elevations in specific IgM antibody levels typically occur three to five days after the onset of symptoms in response to viral infections. The presence of these antibodies generally persists for thirty to sixty days. IgG levels typically become elevated after ten to fourteen days and may remain detectable for years.

Since each person’s seroconversion process is different, it is important to identify both IgG and IgM seperately. Together, the IgM and IgG assays can identify antibodies in symptomatic and asymptomatic individuals.

IDS offers the following antibody tests, for use in a laboratory setting:

  • TGS COVID-19 IgG is a fully automated QUANTITATIVE chemiluminescent test for identifying individuals with an adaptive immune response to SARS-CoV-2, indicating recent or prior infection.

When effective SARS-CoV-2 vaccines becomes reality, the level of antibodies is an important indicator of a person’s immune response to the virus. Thus, the SARS-CoV-2 antibody response levels may help determine the effectiveness of vaccines and therapies.

  • TGS COVID-19 IgM is a fully automated chemiluminescent test to qualitatively detect antibodies that emerge early in the course of infection.

The automated IgG and IgM tests can be used together on the IDS system, to provide the most accurate view of the patient’s immune response. A 95.8% positive sample agreement with RT-PCR after 7 days of diagnosis and 98.6% agreement with presumed negative samples when the IgM and IgG results are combined together.

 

iEuropean Commission (2020). Guidelines on COVID-19 in vitro diagnostic tests and their performance (published 15 April 2020). https://ec.europa.eu/info/sites/info/files/testing_kits_communication.pdf

COVID-19 Testing Solutions

Portfolio Certification Clinical Area Product Type RUO/IVD
Coronavirus Ag Rapid Test Cassette (Swab)

CE Marked

Manual IVD
SARS-CoV-2 Antigen Rapid Test Kit

CE Marked

Manual IVD
TGS COVID-19 IgM

CE Marked

Automated IVD
ErbaLisa® COVID-19 IgM

CE Marked

Manual IVD
ErbaLisa® COVID-19 IgG

CE Marked

Manual IVD
TGS COVID-19 IgG

CE Marked

Automated IVD

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