Examinations
Examinations
The spike protein is one of the four structural proteins (S, E, M, and N) that form the envelope of the SARS-CoV-2 virus. The S protein gives the virus its crown-like appearance, visible under a cryo-electron microscope, and plays a key role in allowing the virus to enter cells, making it infectious.
When the infection enters the body, the immune system begins producing specific antibodies, or immunoglobulins. The detection of S antibodies allows the presence of an immune response generated after infection or vaccination to be determined.
The results of this test should be interpreted by a physician alongside other clinical indicators. While a positive result indicates that an immune response has been established, the duration and level of protection may vary.
Note: This is a semi-quantitative test, and the results are not expressed in specific units.
- Avoid food intake for 2 hours before coming for the test.
- To assess the immune response, it is recommended to test for quantitative antibodies to the spike (S) protein of Covid-19 IgG 42 days after the first vaccine dose.
The test is required to determine whether immunity against Covid-19 has developed and whether the infection has resolved.
- IgG is an indicator of immunity:
- A positive result indicates prior exposure to the Covid-19 virus.
- IgG antibodies typically become detectable 10–14 days after the onset of symptoms.
- A positive IgG result also signifies immunity and protection against reinfection. However, it remains uncertain how strong this protection is and how long it will persist in the blood.