Are antibody tests (Covid-19 Rapid Diagnostic Test Kits) reliable?

To evaluate the level of accuracy of antibody tests, there are 2 criteria to look for:

1-    Sensitivity: The rate of capturing the disease marker intended to be detected (in these tests, the disease marker is the antibody density).

2-    Specificity: The rate of capturing the specific antibodies that should develop against the disease (not to be confused with other antibodies).

The specificity and sensitivity rates act opposite to each other in some terms. High sensitivity rates may decrease the specificity rate of a test, since high level of sensitivity may cause the test to react with any other antibody in the body (may indicate what you do not intend to detect). High level of specificity, on the contrary, may reduce sensitivity, since even the smallest molecular changes in the structure of antibodies may prevent the test from finding its target. More clearly, sensitivity can be considered as the rate or correct positive results and specificity can be considered as the rate of correct negativity results.