Antibody tests may give false positive results (for example, if antibodies to another type of coronavirus are detected) or negative even in infected patients (for example, if antibodies have not yet been developed in response to the virus).

Understanding antibody test results

ARCpoint Labs COVID-19 viral testing can detect coronaviruses other than SARS-CoV-2, such as those that cause the common cold, leading to false positive tests when the test is performed in a population with a low incidence of COVID-19. The prevalence of SARS-CoV-2 antibodies in the test population at a given time influences the positive predictive values ​​of SARS-CoV-2 antibody tests.

Predictive values ​​are probabilities derived from the sensitivity and specificity of a test. The predictive value decreases as prevalence decreases. It suggests that highly specific COVID-19 antibody tests should be performed in low-prevalence settings.

A low positive predictive value may result in more false positives. It could mean that they did not develop antibodies against the virus even though the test showed they were. Suppose the high positive predictive value of a positive SARS-CoV-2 antibody result cannot be achieved with a single test result. In that case, the two tests can be combined to identify better those who test positive for SARS-CoV-2 antibodies.

The accuracy of the test and the time it takes for your body to produce antibodies after you’ve been infected with the coronavirus are two factors that can cause test results from different labs to differ.

Antigen tests and antigen tests are two different types of tests for covid19. No antibodies to SARS-CoV-2 were found in her sample, which resulted in a negative test result for antibodies to SARS-CoV-2.

A false negative is when the result is incorrect. Previously had COVID19 but did not have or did not develop detectable antibodies. It is unclear whether all infected individuals will have a detectable antibody response.

There are several reasons why a negative antibody test result does not guarantee that you are not infected with SARS-CoV-2 or have never been infected. For example, if you are tested immediately after being infected with SARS-CoV-2, the result may be negative because the body needs time to develop an antibody response. It is also unclear whether antibody levels drop over time to undetectable levels.

Summary

The COVID19 antibody test, also known as a serology test, is a blood test used to determine if you have ever been infected with SARS-CoV-2, the virus that causes coronavirus disease (COVID19). Antibody tests cannot tell you if you are currently infected with the COVID19 virus.