How the neutralizing antibody laboratory test works
What does a neutralizing antibody test examine?
Our immune system can form various antibodies against the SARS-CoV-2 virus. The type of antibodies formed depends, among other things, on whether you have undergone an infection or received a vaccination. An evaluation of the actual protection (immunity) by antibody determination is currently only possible to a limited extent. Neutralizing antibodies can be formed both by the vaccination and by a past infection. These prevent the carrier from becoming infected with the SARS-CoV-2 virus. The neutralizing antibodies against the receptor binding domain of the SARS-CoV-2 virus prevent the virus from binding to the ACE2 receptor of the human host cells and block cellular infiltration and virus replication. As a result the virus cannot replicate in the body and is eliminated more quickly by our immune system.
Our SARS-CoV-2 neutralizing antibody test allows quantitative determination of these neutralizing antibodies compared to a conventional (purely qualitative) rapid antibody test.
How does the neutralizing antibody test work?
A small puncture in the fingertip is used to detect neutralizing antibodies to SARS-Cov-2 using one to two drops of blood. To determine the number of neutralizing antibodies, immunochromatography is used in combination with europium nanoparticles. This allows time-resolved fluorescence immunoassays (TRFIA: Time-Resolved Fluorescence ImmunoAssay) to be performed.
In the TRFIA method the amount of neutralizing antibodies against the SARS-CoV-2 virus can be determined by using fluorescent europium nanoparticles (chemical element belonging to metals). The present antibodies from the blood of the test subject bind to the fluorescent europium nanoparticles and to specific antigens on the test strip. The more antibodies present the more fluorescent europium nanoparticles are fixed on the test strip and the stronger the fluorescence. The amount of antibodies present in the blood can thus be determined by the strength of the emitted fluorescence. The results are extremely low detection limits with simultaneous high sensitivity.
Immunofluorescence therefore allows an exact quantitative determination (result in BAU/ml), whereas a conventional rapid antibody test cannot quantify an exact result.
Following this procedure the result is sent after 20-30 minutes.
What distinguishes our test method from a regular rapid antibody test?
A regular rapid antibody test can only provide an indication of whether antibodies are present by determining antibodies, but not how many. Therefore these tests can only give a qualitative result ("yes" or "no"). The test method we use (TRFIA) can, by means of the mechanism described above, give an indication of the amount of antibodies present in the blood by measuring the intensity of the fluorescence. This way the result is much more accurate and also gives information about the antibody status and thus the immune capability.
The test in 3 steps
Take a sample
One to two drops of blood are taken through a small puncture in the fingertip.
The sample is sent to our laboratory where it is evaluated under the appropriate conditions.
The test result
The result is available within
20-30 min. and provides information about the quantity of the antibodies.