We know this about antibody testing

Antibody tests are different from coronate tests and can show if you have antibodies to covid-19 in your blood. Antibodies are a type of protein that is formed by the body's immune system and usually protects against future infections.

• Platform Tests: Laboratory tests performed by healthcare professionals and sent to hospital-affiliated laboratories for analysis.
  
• Quick tests: Performed by health care professionals and takes about 15 minutes, is considered to be of varying quality.
  
• Self-tests: Ordered home and the sampling and analysis is done by the individual himself. However, the Swedish Medicines Agency strongly discourages use.

So far, they have not been used to any great extent due to the fact that the state of knowledge is limited and that the test system is still under development. The platform tests are judged to be good, while the quality of quick tests varies widely.

There is also a risk of testing for antibodies prematurely in the course of the disease. It can result in a negative test response even if you have been infected by the coronavirus. This is because antibodies are formed only some time after you become ill in covid-19. It has not been possible to detect antibodies in the blood of corona patients until 1-2 weeks after the onset.

Both private healthcare providers and commercial companies already offer rapid tests of private individuals.

Karin Tegmark-Wisell, Head of Department at the Public Health Authority answers as follows:

- Some methods look very promising and have high sensitivity and accuracy. But we still think that waiting for this type of antibody testing and broad testing at the individual level still feels premature. At the same time, the test quality increases every week, she says.

Tests conducted in laboratory conditions have shown that antibodies after infection provide protection against the progression of the infection. But it is unclear how long it protects or how many antibodies are needed to protect.