COVID-19 testing is complex with different types and different ways of being tested put in place. Even then, the testing has also changed over time to become more refined and/or faster all at the same time. Of course, this may be confusing to the general public about the type of tests available. This information changes daily.
As of right now, there appears to be 3 types of tests for COVID-19: PCR, antibody, and antigen. The antibody tests were some of the first developed and given emergency use authorization by the Food and Drug Administration in April. Mount Sinai Hospital in New York City under Florian Krammar helped to pioneer this work. The antibody tests for immunity, whether or not a person has developed antibodies or immunity to COVID-19. These results from these tests take time though to be produced and it is also a blood test so somewhat invasive.
Meanwhile, the PCR test is a nasopharyngeal swab test which determines if one has the presence of absence of disease but does not test for immunity. This test has become more widespread at various testing centers. Recently, Abbott labs has come out with an antigen test which also tests for disease presence of absence and can produce results in minutes. It can also be taken by nasal swab or throat swab. It is said to have high sensitivity and specificity. The saliva test by Yale called SalivaDirect also tests disease presence or absence and is said to be quicker and easier to administer than the PCR tests. With these improved tests for disease over the PCR tests, they are sure to improve contact tracing since they are better tests and provide results much faster.
Still, we need to understand immunity better as well in the general population and that still seems best obtained by the antibody tests. Some rapid antibody tests have been developed and this could also greatly aid our understanding of not just disease presence or absence in a community but also the possibility of prior exposure and immunity to COVID-19. This is what is needed to move forward to help reopen society and hopefully to overcome disease.
Written by Usha Govindarajulu