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Bosch develops rapid test for Covid-19

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Re: Bosch develops rapid test for Covid-19

#112
post #64

More important question is, do we trust them?

Bosch is a huge company (400.000 employees). Don't drive your car if you don't trust them.

They are also owned by a charitable foundation whose express goal is the long-term welfare of the company and its employees, so they have much less pressure to extract short-term value.

Re: Bosch develops rapid test for Covid-19

#113

Earlier quoted context omitted.

Practicing hospital physician here. We never use the term "accuracy" to describe diagnostic tests, and whenever I see that term used, I'm very suspicious of the claim being made. In other words, this Bosch announcement can probably be ignored. We use the terms "sensitivity" and "specificity" to describe diagnostic test performance, and never to my knowledge talk about a test's "accuracy." Usually accuracy refers to t…

Accuracy = (Sensitivity + Specificity) / 2. The measure does sometimes get used when discussing diagnostic tests - for an example from psychology/psychiatry see https://insar.confex.com/insar/2019/webprogram/Paper29391.ht...

No, accuracy is the same here it is for any binary classification. accuracy = (true positives + true negatives) / all samples. A largely useless measure. As a single score F1 score is much better, but sensitivity and specifity are specified separately for good reason. It makes napking math much easier, for one thing.

Re: Bosch develops rapid test for Covid-19

#114
This test is made for use at the point of care, apparently all the operater has to do is insert a swab into a cartridge and put it into the device. [0] Comparing the throughput to fully automated systems used in testing labs [1] (look at this beast!) or qPCR machines in research labs [2] is missing the point, those require high investment or skilled staff. A test that can be run quickly by any doctor would be very useful to rapidly detect new outbreaks in the time following the current lockdowns.

However I suspect that the downside of this device will be the high cost of consumables, as is common for microarray biochip based devices.

[0] https://www.youtube.com/watch?v=jgW2pYmzcco [1] https://diagnostics.roche.com/us/en/products/systems/cobas-8... [2] https://www.bio-rad.com/en-us/product/cfx96-touch-real-time-...

Re: Bosch develops rapid test for Covid-19

#115
post #56
post #39

Earlier quoted context omitted.

This article [0] suggests that false negative results will not be as problematic if we manage to start screening on a population level. Inaccuracy of up to 15% could still keep the viral R0 under 1.0 (the critical value for eliminating an epidemic). From the article: > "False negative rates up to 15% could be tolerated if 80% comply with testing, and false positives can be almost arbitrarily high when a high fraction…

Shouldn't we optimize for a higher number of false positives? In the end, sending someone in quarantine for 2 weeks without them being infected is probably less dangerous than a false negative. So making tests overly sensitive would seem more applicable to me here.

If you're quarantining a large number of medics then that's potentially serious and possibly more dangerous overall if your numbers are off.

Re: Bosch develops rapid test for Covid-19

#116

This test is made for use at the point of care, apparently all the operater has to do is insert a swab into a cartridge and put it into the device. [0] Comparing the throughput to fully automated systems used in testing labs [1] (look at this beast!) or qPCR machines in research labs [2] is missing the point, those require high investment or skilled staff. A test that can be run quickly by any doctor would be very us…

It's like a Keurig single serve coffee machine but for covid-19 testing

Re: Bosch develops rapid test for Covid-19

#117

Earlier quoted context omitted.

Practicing hospital physician here. We never use the term "accuracy" to describe diagnostic tests, and whenever I see that term used, I'm very suspicious of the claim being made. In other words, this Bosch announcement can probably be ignored. We use the terms "sensitivity" and "specificity" to describe diagnostic test performance, and never to my knowledge talk about a test's "accuracy." Usually accuracy refers to t…

Sounds like "Sensitivity" and "Specificity" are analogous to "Accuracy" and "Precision" typically used in data sciences.

I don't really know data science but in assay validation, sensitivity basically measures false negative rate, and specificity measures false positive rate. Accuracy and precision are measures of assay consistency or tightness. (statisticians may not purely agree with my simple explanation)

Re: Bosch develops rapid test for Covid-19

#118
post #98

This is not rapid, only 10 tests/day, whilst the current overly slow sequencers can do 200/day. The accuracy of 5% is also worse than other faster sequencers of 3%. And compare that to modern ThermalFischer parallel PCR sequencers, which operate in realtime, 25 tests in parallel, for 2.500€. That's a factor of 1000. With 10 modern sequencers per city you could test 10.000 per day, eg with drive-in. https://www.thermo…

The accuracy of 5% is also worse than other faster sequencers of 3%

Is that false positives or false negatives or both so to speak? I.e. what is the confusion matrix of these techniques?

Re: Bosch develops rapid test for Covid-19

#119
post #98

This is not rapid, only 10 tests/day, whilst the current overly slow sequencers can do 200/day. The accuracy of 5% is also worse than other faster sequencers of 3%. And compare that to modern ThermalFischer parallel PCR sequencers, which operate in realtime, 25 tests in parallel, for 2.500€. That's a factor of 1000. With 10 modern sequencers per city you could test 10.000 per day, eg with drive-in. https://www.thermo…

You're forgetting the difference between bandwidth and latency.

Re: Bosch develops rapid test for Covid-19

#120

Earlier quoted context omitted.

Yes, and you perfectly demonstrated the confusion possible by selecting the wrong terms. Sure, 'specificity' and 'sensitivity' are scientific terms - but for marketing material, can be confused with emotional responses. Thus, I believe Bosch chose 'accuracy', since this translates into other languages more effectively.

...marketing material? To the non-English world? I was literally just explaining a potentially helpful thought process to an English-speaking HN visitor dev who lists his(?) public key on his profile... not trying to produce marketing material for a French waiter or something. Are you sure you're not the one confused here rather than him?

I'm only trying to point out that Bosch may have specifically chosen the term 'accuracy' instead of 'specificity' or 'sensitivity', which don't translate easily outside of the Anglo-sphere, and in my opinion your thread is a valid example of why those two terms don't get used to market this device, which is what kicked this thread off in the first place ..
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