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> Another promising pathway is to pool many tests and run them together. If a pooled sample tests negative, everyone in the pool is negative. If it is positive,

> Another promising pathway is to pool many tests and run them together. If a pooled sample tests negative, everyone in the pool is negative. If it is positive, the members of the pool can be tested individually. Well, it took a global pandemic, but we finally found a use for bloom filters!

joshuamorton 7y ago
This is not a new thing in medical testing. They do it for donated blood already.
LolWolf 7y ago
This idea is called group testing [0] and has been used by the army for quite a while. It is also a well-studied problem in information theory as a (useful) basic model and we know optimal solutions to it. What is surprising is that group testing tells us that we can actually do better: the specific construction you pinpoint the people who come up positive, without needing to have a test for each person [1] and this result is optimal in the expected number of tests. I'm surprised that most labs haven't already been doing this (but I would suspect some have). Wootters has wonderful notes on the mathematical background for this—I really recommend them. [2] ----- [0] https://en.wikipedia.org/wiki/Group_testing https://en.wikipedia.org/wiki/Group_testing [1] Of course, we require an upper bound on the total prevalence, but even a weak upper bound yields fairly good savings in testing. [2] Page 3 on of http://web.stanford.edu/~marykw/classes/CS250_W18/lectureNotes/Lecture8-compressed.pdf http://web.stanford.edu/~marykw/classes/CS250_W18/lectureNot...
- yshvrdhn 7y ago
  germany has been doing this for a while now
- enchiridion 7y ago
  So you might together the samples before testing?
- LolWolf 7y ago
  Gah, I've passed the editing window. If it's confusing to read, it is supposed to say: > the specific construction lets you pinpoint the people who come up positive
eckesicle 7y ago
We have been working on productizing this for the past couple of weeks. A bottle neck seems to be that it's not really possible to pool more than at most 32 patients at a time. It's an early work in progress but have a look: https://www.pcr-pooling.com https://www.pcr-pooling.com
- efavdb 7y ago
  This is exciting. I've been following the idea for a month or so. Did you know that a group in Israel has tested the idea and found that it worked with the swab tests? I have a link on my notes below. I'll add your site to the reference list at the top tonight. https://github.com/EFavDB/pooling https://github.com/EFavDB/pooling
  - eckesicle 7y ago
    Hi, Yes we are aware and have reached out to them. There are a few more studies out there. One from Stanford and one from Germany too. We're currently working to refine the software and also improve the presentation (there are some mistakes) and write a paper.
pmiller2 7y ago
It's also the solution to a fun puzzle/brain teaser: https://www.geeksforgeeks.org/puzzle-19-poison-and-rat/ https://www.geeksforgeeks.org/puzzle-19-poison-and-rat/
deleted 7y ago
[deleted]

joshuamorton 7y ago

This is not a new thing in medical testing. They do it for donated blood already.

LolWolf 7y ago

This idea is called group testing [0] and has been used by the army for quite a while. It is also a well-studied problem in information theory as a (useful) basic model and we know optimal solutions to it. What is surprising is that group testing tells us that we can actually do better: the specific construction you pinpoint the people who come up positive, without needing to have a test for each person [1] and this result is optimal in the expected number of tests. I'm surprised that most labs haven't already been doing this (but I would suspect some have). Wootters has wonderful notes on the mathematical background for this—I really recommend them. [2] ----- [0] https://en.wikipedia.org/wiki/Group_testing https://en.wikipedia.org/wiki/Group_testing [1] Of course, we require an upper bound on the total prevalence, but even a weak upper bound yields fairly good savings in testing. [2] Page 3 on of http://web.stanford.edu/~marykw/classes/CS250_W18/lectureNotes/Lecture8-compressed.pdf http://web.stanford.edu/~marykw/classes/CS250_W18/lectureNot...

yshvrdhn 7y ago
germany has been doing this for a while now
enchiridion 7y ago
So you might together the samples before testing?
LolWolf 7y ago
Gah, I've passed the editing window. If it's confusing to read, it is supposed to say: > the specific construction lets you pinpoint the people who come up positive

eckesicle 7y ago

We have been working on productizing this for the past couple of weeks. A bottle neck seems to be that it's not really possible to pool more than at most 32 patients at a time. It's an early work in progress but have a look: https://www.pcr-pooling.com https://www.pcr-pooling.com

efavdb 7y ago
This is exciting. I've been following the idea for a month or so. Did you know that a group in Israel has tested the idea and found that it worked with the swab tests? I have a link on my notes below. I'll add your site to the reference list at the top tonight. https://github.com/EFavDB/pooling https://github.com/EFavDB/pooling
- eckesicle 7y ago
  Hi, Yes we are aware and have reached out to them. There are a few more studies out there. One from Stanford and one from Germany too. We're currently working to refine the software and also improve the presentation (there are some mistakes) and write a paper.

pmiller2 7y ago

It's also the solution to a fun puzzle/brain teaser: https://www.geeksforgeeks.org/puzzle-19-poison-and-rat/ https://www.geeksforgeeks.org/puzzle-19-poison-and-rat/

deleted 7y ago

[deleted]