Page 53 - SARS-COV-2-laboratory-viral-outbreak-perspective-investigation-by-ICR-NIH-MY

There is still quite an amount of controversy around

the world with regards to the use of serology tests.

I know we have access to some serology kits now.

What is the current situation and what are our

experiences with serology tests?

Dr. Ravi: Serology tests will only tell us about exposure. That’s why we do not use it for
screening. It would be helpful to look at prevalence. There are 2 types of kits, one is the rapid
antibody test, and the ELISA assay. This will tell us about exposure. Usually, IgM peaks
around Day 8 while IgG peaks around Day 14. When we are looking at the samples, some of
them have RTK antibodies that have very good specificity and sensitivity. More importantly,
looking at people who have neutralizing antibodies, it is important to have a neutralizing
antibody test.

Previously, when we did this, we had to grow the virus in the BSL-3 lab. Professor Wang
Linfa of Duke-NUS Medical School, Singapore has developed the cPASS kit, in which its
test ability was to detect neutralizing antibodies, using a BSL-2 lab (no need to grow the
virus). The studies we are looking into in IMR include longitudinal studies, to see how long
the protective antibodies would last, as well as to look at the seroprevalence (collaboration
with NHMS). Therefore, RTK antibodies will only tell us exposure, but more importantly we
need to see if the antibodies are protective antibodies or not, we need to do a special cPASS
test.

Datuk Dr. Chris: RTK antibodies, of course, it shows seroprevalence. We haven’t tested
everyone in Malaysia and this will be a good time to look at how widely spread it is because
we know a large proportion, up to 85-90% of the population may be asymptomatic.

Dr. Arni: At present, our Ministry of Health (MoH) are already using the rapid antibody test.
However, for those who are negative on day 1, the test has to be repeated on day 13 before
they are discharged from home surveillance order. This is part of the public health policy.