PandemicPost Testing

search the Original Green Blog


testing

image via Wikimedia Commons


   There is a lot of backward thinking on testing. Many are saying that you should only be tested if you’re having clear symptoms and/or in a high-risk group. But the most dangerous people are those who are asymptomatic, or who just think they might have a cold or allergies. Because it is these people who can spread it to many more.


  ~Steve Mouzon


C Fenno Hoffman That's why isolation is sooooo important in these first few weeks




Brandon Neary Even the best diagnostic tests in the world will have a small percentage of false positive results. Symptomatic patients with travel and or contact history will have a much higher pre-test probability than the general asymptomatic population and the benefits of testing outweigh the chance of a false positive result. With general population testing, you would end up with far more false positives than true positives and consume health care resources monitoring healthy people


Steve Mouzon Brandon Neary what is a reasonable small percentage of false positives to assume?



Brandon Neary Steve Mouzon I haven’t seen the performance characteristics of the coronavirus tests (they probably haven’t been established yet) but I would not be surprised if I heard it was 5-10% of true negatives that give a positive result. Especially if the test is calibrated for maximum sensitivity. A test that was so rapidly developed could have an even higher rate


Steve Mouzon Brandon Neary 5-10% false positive isn’t really a small number, but let’s think through this. If someone tests positive but is asymptomatic, they certainly won’t be hospitalized. Most likely they’ll be asked to self-quarantine. But what, after handwashing, is considered one of the best practices? Staying home. Help me out with why that’s a bad thing.


Brandon Neary Steve Mouzon In my mind, the hand washing, awareness, and social distancing that is going on now will be more effective than mass testing, although we should almost certainly be more than what has recently been available. The reality is that it would not just be the person with the false positive test who self-quarantines though, most likely it would also be everyone who had interacted with that person in the days preceding the positive test as well.


Steve Mouzon Brandon Neary so you’d rather not know who the asymptomatic carriers are? When lives are at stake, I’d rather know. Here’s the flip side: for them and their close interactors, staying home on a false positive may prevent them from contracting the virus had they gone out.


Brandon Neary Steve Mouzon I think everyone would love to be able to identify all the cases, the diagnostic tests just aren’t capable of doing that. And I say that as someone who has spent 15 years in an R&D capacity developing in vitro diagnostics. The asymptomatic carriers would likely have a low viral load and give a false negative result as well. Definitely no easy answer to the whole situation unfortunately


Steve Mouzon Brandon Neary I’m certainly not a medical person, so you obviously know things I don’t. But if I’m reading so much about identifying Patient Zero & reconstructing webs of relationships & contacts, it seems like knowing who has it is probably an important thing. But time will tell.


Brandon Neary Steve Mouzon agreed, definitely room for all viewpoints and discussion. I love your work, by the way. I have a place out at Carlton Landing which is how I came to follow you


Steve Mouzon Brandon Neary oh, cool! What a fabulous place! Carlton Landing isn’t just excellent, it actually pioneered several important things.

 


Jennifer Hurley Steve, ideally we’d be testing anyone with symptoms and also proactively going into high risk places (like nursing homes and prisons) to test and then trace all contacts of anyone who’s positive, but since we don’t have enough testing capacity, they’re rationing. It’s a huge fail and a big part of why this has gotten so far out of control.


Walk Appeal book front cover

Subscribe to get Walk Appeal book updates

* indicates required


© Stephen A. Mouzon 2020