The Joy of Sharing Science No.2, Everything you need to know about COVID-19 Biology Supplement

Joy of Sharing Science
PCR tests can be very labor-intensive, with several stages at which errors may
occur between sampling and analysis. False negatives can occur up to 30% of
the time with different PCR tests, meaning they’re more useful for confirming
the presence of infection than giving a patient the all-clear. (Forsanari,“Testing
Individuals for COVID-19”)
Two common types of PCR testing are Nested PCR and Real-Time PCR.
Nested PCR: The nested PCR is useful for amplifying genes present in low
abundance. Product from one round of PCR using “outer primers” to amplify
a large fragment of the rRNA gene is used as a template in the second round
of PCR that targets a smaller region of the amplicon using “inner primers.”
Real-Time (Quantitative) PCR: Real-time PCR or quantitative PCR or qPCR
is an in vitro technique to quantify the presence of DNA templates
(Dhanasekaran et al., 2014). It is used to amplify and simultaneously quantify
a targeted DNA molecule.
Antibody Tests
This is a blood test. It looks for
antibodies to the coronavirus. Your
body produces antibodies in response
to an infectious agent such as a virus.
These antibodies generally arise after
four days to more than a week after
infection, so they are not used to
diagnose current disease.
Interesting Note: An antibody test tells
us what proportion of the population
has been infected. It won’t tell you who
is infected, because the antibodies are
generated after a week or two, after
which time the virus should’ve been
cleared from the system. But it tells you
who’s been infected and who should be
immune to the virus.