Types of Tests There are two different types of tests – diagnostic tests and antibody tests. A diagnostic test can show if you have an active coronavirus infection and should take steps to quarantine or isolate yourself from others. An antibody test looks for antibodies that are made by your immune system in response to a threat, such as a specific virus. Antibodies can help fight infections. Antibodies can take several days or weeks to develop after you have an infection and may stay in your blood for several weeks or more after recovery.