Thread by @ElliTheelPhD

Lots of questions about the role of serologic testing for #COVID19 over the past few days.

So, my $0.02:

1. We do not diagnose other respiratory infections w/ serology...#SARSCoV2 is no different.

2. Initial studies from China suggest seroconversion occurs in most pts around Day 11 (preprint below).

What this means is that serology is:

✔️#NotHelpful for Dx of acute/symptomatic infection.

✔️#DefinitelNotHelpful at the POC! 😱🤯

medrxiv.org/content/10.110…

Regarding specificity, although there are some epitope differences by crystal stx between the spike protein of #SARSCov2 and other coronaviruses, we really do not know ANYTHING about the specificity of these COVID19 ELISAs yet.

Hopefully we’ll have some data soon

What role does serology play then?

✔️The obvious one (w/ a sens/spec enough assay) is seroprevalence studies, which are important from a public health perspective.

✔️Identification of individuals with neutralizing antibodies to #SARSCoV2

Hyper-immune plasma was used historically to treat ill patients & efforts are underway to see if this strategy can be used today while we await vaccines and targeted antivirals!
jci.org/articles/view/…

To clarify, yes, serologic assays can be used to detect antibodies to the virus, indicating infection at some time point.

My point here is that b/c seroconversion takes time, use of Ab tests to diagnose acutely ill patients, (at the POC as some assays claim) is worriesome (IMO)