Thanks very much James for sharing this. In New Zealand groups of academic public health medicine docs are starting to write and peer review rapid reviews related to Covid-19 and I have shared your post with our local co-ordinator.
I assume that similar groups around the world are doing similar things, so could I please strongly encourage list members to follow the example set by James and share these and also peer review them.
I just did a rapid critique of your review James and thought it was excellent.
James, on a related topic, In your last post you mentioned that the specificity of PCR was pretty much 100%. I discussed this with colleagues and we agreed that even if there are possibly a few false positives, we should assume there are none.
A much more complicated issue is the so-called ‘false negative rate’ (i.e. the proportion of all negative tests that are false), which one of my colleagues conducted a rapid review on. This is actually 1 minus the negative predictive value (NPV) and for
the pedantic is a proportion, not a rate. But the key point is that, like the positive predictive value (PPV), it is highly dependent on the pretest probability (disease prevalence) in those tested. A study in asymptomatic French nationals who had been in
Wuhan found a false negative proportion of 0, while another study of older Chinese people with CT evidence of viral pneumonia, found a false negative proportion of 80%. I thought this was a good reminder that the PPV and NPV are highly context specific.
Cheers Rod Jackson
University of Auckland
New Zealand
Hi Everyone
Just posted our first COVID-19 Rapid Review - Tools for Practice. All about hydroxychloroquine. It
will take you just a few minute to read and you will be up-to date as of now, but things are changing hourly as
we all know.
Will have one soon on assessing dyspnea virtually.
James
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