Summary and Perspective
Specificity and sensitivity are two fundamental requirements for an
effective diagnosis. It is also important that the testing method is
user friendly. RNA detection is the most frequently used method for the
identification of COVID-19 patients because this method is extremely
sensitive due to the power of nucleic acid amplification and also highly
specific by using complementary nucleic acid probe/primer for the
identification of a particular RNA. The major drawback in such an
emergency situation is probably the requirement of well-trained
personnel and lengthy testing time (usually 3-4 hours) to run the test.
However, NAAT has been announced that positive/negative COVID-19 can be
determined in about 10 minutes by using the isothermal amplification
method. This may due to the simplification of the NAAT procedure and the
high amount of the SARS-CoV-2 at the beginning of the infection be
detected.
Detection on viral proteins, such as S and N protein, give complementary
information to that of RNA detection from the same sample. This method
is more direct (without amplification), but is less sensitive. It needs
more effort to obtain a suitable probe (usually antibody), but the
testing method can be simple. Recent developments in biosensing
technologies can significantly improve the protein sensing sensitivity
such as the use of magnetic bead to concentrate the protein molecules or
by applying nanowire field-effect transistor as a transducer. Many of
the entrepreneurs may take this opportunity to fasten their product
development. Serology testing targeting on viral-induced antibodies is
given different information as those for viral RNA and proteins from
SARS-CoV-2. Although the protein testing method is similar, the targets
are not part of the virus and the testing specimens used can be quite
different as compared to those for viral protein detection.
It is unfortunate that the world is currently suffering from the
COVID-19 epidemic. However, we can expect that such an incident will
re-appear. We wish that the world will be better prepared every time
when we face the potential spread of an infectious disease. Biosensing
technologies have progressed rapidly in the past decade. The pandemic
outbreaks of COVID-19 continue to remind us that diagnostic tools are
critical and needed to be prepared in advance.