SARS-CoV-2 (COVID-19) diagnostics in E. Gulbja Laboratory


Virus incubation period – the time that elapses from the moment of infection to the onset of symptoms of the disease or the possibility of diagnosing the infection.
In the event of SARS-CoV-2 virus, the most common incubation period is 5-6 days (in rare cases – up to 21 days). After the incubation period, the presence of SARS-CoV-2 virus can be most often detected in the body for 21 days (in some rare cases longer – up to 60 days).
Antibodies (specific antibodies) – proteins developed by the immune system of the human body to provide protection (immunity) against the infection (in this case, the SARS-CoV-2 virus). The body starts producing antibodies immediately after being infected, but, in the event of SARS-CoV-2 virus, it usually takes at least 10-14 days for them to be detected by laboratory methods (analyses/tests). Most often, antibodies remain in the human body for a long period of time – months, years.

To diagnose an acute infection of SARS-CoV-2 virus causing COVID-19 disease, a PCR test (smear) is used.

Gulbis Laboratory offers a test – semiquantitative and quantitative detection of SARS-CoV-2 (COVID-19) antibodies. Test systems of several manufacturers are used for anti-SARS-CoV-2 tests.

Tests for antibodies to Spike proteins are recommended to assess the development of antibodies after vaccination. These antibodies are also detectable in patients after recovery from COVID-19.

The recommended time for antibody level detection is 1 week after taking the second vaccine (for Pfizer vaccine). Available tests include:
 

Anti-SARS-CoV-2 IgG Spike (Chemiluminescence method, Siemens Healthcare GmbH, Germany) – detects specific IgG class antibodies against SARS-CoV-2 virus S1 RBD proteins.
Test code: 3930
The price of the test is EUR 8.00*
 

Anti-SARS-CoV-2 S (Electrochemiluminescence Method, Roche Diagnostics GmbH) – Detects total antibodies (IgM and IgG) against S-RBD antigens of SARS-CoV-2 virus.
Test code: 3960
The price of the test is EUR 12.00*
 

To confirm a pre-existing COVID-19 disease, it is also possible to detect total (IgM and IgG) antibodies to Nucleocapsid proteins of SARS-CoV-2 virus. (Electrochemiluminescence method, Roche Diagnostics GmbH). These antibodies do not respond to vaccine-induced antibodies.

Anti-SARS-CoV-2 – detects total antibodies without differentiating between individual Ig classes, as well as between the acute phase and the recovery phase. It is recommended to perform this test to confirm a history of COVID-19 in patients, who have not been tested for RL-PCR, or who have had a weak positive or marginal PCR response and negative after retesting. It can also be performed in patients, who were tested as positive in the PCR smear test. This test generally determines whether antibodies directly related to COVID-19 are present in the body.
Test code: 3959
The price of the test is EUR 5.00*
 

Test systems developed by EUROIMMUN (Germany) for the detection of IgA and IgG class specific antibodies against S antigens of the virus. The system is used to evaluate the dynamics of the development of individual classes of antibodies in the event of a COVID-19 infection.

Anti-SARS-CoV-2 IgA  is used to identify specific IgA class antibodies that play a role in the protective response of the mucosa due to the secretory component. They appear slightly earlier than IgG or at the same time. In the initial phase of the disease, they occur more often in higher titres than IgG, and later on IgG prevails.
Test code: 3969
The price of the test is EUR 19.85*
 

Anti-SARS-CoV-2 IgG  Detects only IgG antibodies that persist long after the disease. The presence of these antibodies points to persistent immunity to COVID-19. This test is recommended for patients who have had a confirmed COVID-19 infection and who want to determine the dynamic change in antibodies or who have had symptoms similar to the symptoms of COVID-19 in the last 6-9 months.
Test code: 3979
The price of the test is EUR 19.85*
 

*- prices are indicated without the costs of serum collection and processing (Price – EUR 1.80)
 

It is recommended to evaluate the antibody test results in relation to the molecular PCR test result:

  1. The new coronavirus SARS-CoV-2 (RT-PCR) = NEGATIVE and Anti-SARS-CoV-2 antibodies = NEGATIVE:
    Negative results indicate that SARS-CoV-2 virus has not been detected in the test material and that no virus-specific antibodies have been detected in the blood sample. This allows one to conclude that you, most likely, have not been infected and/or sick with the virus that causes COVID-19.
    Follow the national guidelines for controlling the COVID-19 pandemic. If symptoms of COVID-19 appear in the following days or later, repeated testing is recommended.
  2. The new coronavirus SARS-CoV-2 (RT-PCR) = NEGATIVE and Anti-SARS-CoV-2 antibodies = POSITIVE:
    A negative SARS-CoV-2 RNA test indicates that no virus is present in the sample at this time.
    A positive Anti-SARS-CoV-2 test points to the presence of specific antibodies to the SARS-CoV-2 virus, which, most likely, points to having had a previous infection and/or disease.
    The presence of antibodies is an indicator of the development of immunity to the SARS-CoV-2 virus. Repeated antibody testing after 2-3 months should be performed to confirm continued immunity.
  3. The new coronavirus SARS-CoV-2 (RT-PCR) = POSITIVE and Anti-SARS-CoV-2 antibodies = NEGATIVE:
    A positive SARS-CoV-2 RNA test indicates that SARS-CoV-2 virus has been detected in the sample.
    A negative Anti-SARS-CoV-2 test indicates that at this stage the body has not yet developed specific antibodies to the SARS-CoV-2 virus in detectable amounts, which, most likely, is an indication of the initial stage of the disease.
    You are infectious due to the detected virus – stay in isolation. Strictly follow the instructions of your attending physician and epidemiologist and repeat the tests accordingly.
  4. The new coronavirus SARS-CoV-2 (RT-PCR) = POSITIVE and Anti-SARS-CoV-2 antibodies = POSITIVE:
    A positive SARS-CoV-2 RNA test indicates that SARS-CoV-2 virus has been detected in the sample.
    A positive Anti-SARS-CoV-2 test points to the presence of specific antibodies to the SARS-CoV-2 virus, which is an indication of an immune response in the body.
    You are still infectious due to the detected virus – stay in isolation. Strictly follow the instructions of your attending physician and epidemiologist and repeat the tests accordingly.

The blood for the test can be provided in any patient service centre of E. Gulbis Laboratory, however patients who have to observe self-isolation may only provide their blood for this test by pre-appointment, by calling + 371 67801112, and only at dedicated collection points.

 

SELECTION OF ANTIBODY TESTS IN DIAGNOSTICS OF COVID-19

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rRT-PCR and Anti-SARS-CoV-2 IgA and IgG dynamics

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Interpretation of SARS-CoV-2 test results

 

Real time PCR SARS-CoV-2 Anti-SARS-CoV-2 IgA Anti-SARS-CoV-2 IgG
Early phase of an acute infection

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Late phase of an acute infection

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Previous infection

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Dynamic control required (after 2 weeks)

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