In recent days, people with signs and symptoms of COVID-19 have gone to private labs in SMA to get a Diagnostic Test for the disease and instead received an Antibody Test without knowing there was a difference. The consequences of this are potentially VERY DANGEROUS for the spread of COVID-19. Part of this is language barrier, part of this is misinformation happening at the testing sites. So, it is very important you understand the differences between these two types of tests.
Let’s talk about it….
Diagnostic Tests vs. Antibody Tests – The Differences
Diagnostic:
- A diagnostic test can show if you have an active coronavirus infection and whether you should take steps to quarantine or isolate yourself from others.
- It is always tested by a nasal/throat swab or by saliva (saliva is rare). It is never a blood test.
- Currently there are two types of Diagnostic Tests – molecular (RT-PCR) tests that detect the virus’s genetic material, and antigen tests that detect specific proteins on the surface of the virus.
- The molecular test is highly accurate and can take days for a result. The antigen test has rapid results (in an hour or less), but is not as accurate and negative result should be confirmed with a molecular test.
- The FDA formally evaluates these tests prior to use.
Currently there are no Home Test Kits for the rapid detection of COVID-19 infection. There are Home Collection Kits available in some countries, but these require you to take your own nasal swab and the test has to be sent into a lab. We recommend, that all swab samples should be collected by a healthcare provider to ensure accurate collection as this ultimately affects results.
Antibody:
- An antibody test looks for evidence of someone’s prior infection with the virus. The test provides evidence that someone may have been exposed to the virus in the past, even if they did not have symptoms, by detecting antibodies specific to the virus.
- It is always tested by a blood sample, either a finger stick or blood draw
- The results from an antibody test are rapid (results in as little as 15 minutes) and accuracy is dependent upon the test itself, as well as the prevalence of disease in the community. The less disease present, the less accurate the positive results are (for example, at this time, 2/3 of positive results in SMA on the very best test available would be false)
- There are Home Test Kits available and these require a finger stick for blood.
- The FDA has not formally evaluated these tests, though several have been given Emergency Use Authorization.
Remember: the antibody test does not diagnose an active infection or identify who is protected from reinfection (antibodies have not been proven to guarantee immunity).
https://www.fda.gov/consumers/consumer-updates/coronavirus-testing-basics
COVID-19 SMA goal is to provide accurate, up to date, healthcare resources and information about COVID 19 and the San Miguel de Allende community in a context which information that is rapidly changing.