COVID**9 testing involves analyzing samples to assess the current
or past presence of SARS-CoV*2. The two main branches detect either
the presence of the virus or of antibodies produced in response to
infection. Molecular tests for viral presence through its molecular
components are used to diagnose individual cases and to allow
public health authorities to trace and contain outbreaks. Antibody
tests (serology immunoassays) instead show whether someone once had
the disease. They are less useful for diagnosing current infections
because antibodies may not develop for weeks after infection. It is
used to assess disease prevalence, which aids the estimation of the
infection fatality rate.