The COVID-19 tests that require nasal swab samples are the PCR test and Antigen test as they collect samples of cells and fluids from your respiratory system. It enables the identification of specific genes for the SARS-CoV-2 virus that causes COVID-19. The specimen is collected using a long nasal swab that is inserted into the passageway between the nose and the back of the throat.
Antibody testing, also known as a serology test, consists of blood being drawn from a patient’s finger that may identify past infection of the virus that causes COVID-19. It’s a test that looks for evidence of the body’s immune response to the virus.
For more information on COVID-19 nasal swab tests see this CDC article.