
Saliva based Covid test: results in 45 minutes - goldenshale
https://www.colorado.edu/today/2020/07/22/new-covid-19-test-returns-results-45-minutes-without-nasal-swab
======
chris_va
Technically, you are really just waiting for the thermal inertia of the
testing device. The reaction kinetics are really quite fast.

During the last SARS outbreak, this sort of thing was proposed:
[https://pubs.rsc.org/en/Content/ArticleLanding/2011/AN/c1an1...](https://pubs.rsc.org/en/Content/ArticleLanding/2011/AN/c1an15365j#!divAbstract)

... to do 3 minute tests. I assume grant funding dried up, since who could
guess that after 2 outbreaks that we'd have a 3rd?

~~~
redis_mlc
> I assume grant funding dried up, since who could guess that after 2
> outbreaks that we'd have a 3rd?

Yes, that's what I've read. Any US research scientists still working on SARS-1
after 2003 were told "you're on your own."

Kudos to Canada for being as diligent as Taiwan in attacking COVID-19 - they
remember it wiping out Toronto hospital staff in 2003. Check out the Youtube
CBC channel for their impressive nation-wide mobilization.

Makes you wonder wtf Chinese virology labs were doing for 20 years with
coronavirus if they weren't working on a cure, doesn't it? (There's 40 labs
total across China.)

~~~
ethbro
_> Makes you wonder wtf Chinese virology labs were doing for 20 years with
coronavirus if they weren't working on a cure, doesn't it? (There's 40 labs
total across China.)_

Like most things in a command economy, they worked on whatever was a political
priority.

I'd hazard to guess it wasn't a priority in the intervening years for the same
reason there was little free market incentive to address it: yes, it's bad
when it happens, but it doesn't happen that often.

Ergo, they were probably just as starved of resources.

The preexisting US effort was mostly funded through DARPA for the same
reasons. [https://www.darpa.mil/our-research](https://www.darpa.mil/our-
research) (e.g. ADEPT, P3, Prometheus, PREPARE)

------
war1025
Off topic, but related enough that I feel its relevant to mention:

I learned this week that many blood donation and plasma centers [1][2] are
doing Coronavirus antibody tests for anyone* that donates right now.

I've heard a lot of people in my social / online circles comment how they wish
they knew whether or not they had antibodies. Seems like a great way to find
out.

[1] [https://www.redcrossblood.org/donate-
blood/dlp/covid-19-anti...](https://www.redcrossblood.org/donate-
blood/dlp/covid-19-antibody-testing.html)

[2] [https://www.lifeservebloodcenter.org/donate/recovered-
covid-...](https://www.lifeservebloodcenter.org/donate/recovered-
covid-19-patient-plasma-donation/)

* Probably not literally anyone, but it sounds like they are giving them out pretty freely.

~~~
pmoriarty
_" I've heard a lot of people in my social / online circles comment how they
wish they knew whether or not they had antibodies"_

What people need to realize is that the important questions are not whether
you've got antibodies but:

1 - whether you'll sick when you're exposed to the virus again

2 - how sick you'll get the next time around

No one knows the answers to these questions yet, and we also don't know how
antibodies bear on the answers to these questions.

It is possible that even with antibodies you'll still get sick if you're
exposed to the virus (as we know is the case for some other diseases), and
even if antibodies play some role in how sick you'll get it's possible that
(again, as is the case with some diseases) repeated exposure to the virus will
cause even greater illness than the first time around.

People shouldn't be assuming that having antibodies means they're immune.. we
just don't know enough yet to say whether that's true or not.

Even if it is true, there might be a certain level of antibodies that are
required to have a certain level of immunity, and we don't know yet what level
of antibodies are necessary, nor the kind of antibodies necessary,

Finally, even if antibodies do grant immunity, we don't know how long that
immunity would last, nor if such immunity varies from person to person for
some not yet known reason.

~~~
sroussey
Dengue fever antibodies make the second infection lethal.

~~~
splittingTimes
IIRC, Dengue has 4 different strains. When you get reinfected with the same
strain, then you are good. Getting one of the other strains is the problematic
case.

------
ilyagr
This reminds me of an excellent video on use of cheap and less sensitive tests
on "This Week in Virology".

[https://youtu.be/kDj4Zyq3yOA](https://youtu.be/kDj4Zyq3yOA) (Feel free to
skip to around 6:35).

Preprint:
[https://www.medrxiv.org/content/10.1101/2020.06.22.20136309v...](https://www.medrxiv.org/content/10.1101/2020.06.22.20136309v2)

Update: the colorado.edu article also links to this preprint when it discusses
the "separate computer modelling study".

~~~
acqq
The visual explanation of the ideas and concepts presented there, also
mentioned in the later podcast:

Medcram: “Coronavirus Pandemic Update 98: At Home COVID-19 Testing - A
Possible Breakthrough”

[https://www.youtube.com/watch?v=h7Sv_pS8MgQ](https://www.youtube.com/watch?v=h7Sv_pS8MgQ)

Also, regarding the Ct value, from:

“Interpreting the COVID-19 Test Results: a Guide for Physiatrists”

[https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7268832/](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7268832/)

In PCR tests “the diagnosis is made based on the threshold cycle (Ct) value.
Ct is defined as the cycle number when the sample fluorescence exceeds a
chosen threshold above the calculated background fluorescence.5 In other
words, the lower the Ct value of a specific gene, the more the gene exists in
the sample. However, the problem with a Ct-based diagnosis is that there is no
absolute or constant Ct cut-off value, and Ct cut-off values are different for
each diagnostic reagent even for the same gene.”

------
faitswulff
The study "Saliva is more sensitive for SARS-CoV-2 detection in COVID-19
patients than nasopharyngeal swabs" [0] was published in April, so I'm glad
some additional steps have been taken to test it.

[0]:
[https://www.medrxiv.org/content/10.1101/2020.04.16.20067835v...](https://www.medrxiv.org/content/10.1101/2020.04.16.20067835v1)

------
Symmetry
This seems like a really good idea but I worry about regulatory approval.
Tests like these will tend to catch any Covid-19 cases in the window where you
have a real chance of infecting someone from maybe 2 days pre-symptom onset to
a few days post onset. And that's really all you need from an epidemiological
standpoint. But from a medical standpoint if someone comes into your ER a week
post symptom onset you want to know if they've got Covid-19 whether or not
they're still infected, from a medical standpoint. And in that use case this
is less likely to produce the correct answer than the already existing PCR
test and the time lag probably isn't that important. It would be reasonable to
allow it anyways but the FDA's rules are set up for the benefit of medical
uses rather than epidemiological uses and I wouldn't be optimistic about it
getting allowed baring pressure from above.

Also

>One researcher spiked 30 out of 60 saliva samples with inactivated SARS-CoV-2
in the lab. Then they shuffled the samples and gave them to another scientist
to test with the RT-LAMP technology.

I wonder if that required a BSL-3 facility or not. Generally you can do
medical work on this virus with any sort of facility or laboratory you have on
hand but you're only allowed to do science involving the virus if you have a
special laboratory with negative pressure and special failsafes and so on.

~~~
icegreentea2
Spiking inactivated virus does not require BSL-3. You only need BSL-3 for
isolating and growing live virus. So the vendors that create inactivated virus
are doing so in BSL-3 facilities, but once it's inactivated you can work with
it at much lower stringency. Seems like BSL-2 is standard.

------
rusbus
This test relies on RT-LAMP to generate copies of the RNA instead of PCR which
the "regular" tests use. It's pretty sensitive, but not as sensitive as state
of the art PCR[1]. It's also way faster. No magic, just a slightly different
technique with different trade offs.

[1]
[https://www.frontiersin.org/articles/10.3389/fmicb.2018.0208...](https://www.frontiersin.org/articles/10.3389/fmicb.2018.02089/full)

------
postingawayonhn
They've been using a saliva test here in Australia for several weeks for
children and others who struggle with the nasal swab. Accuracy is apparently
only 87% though.

[https://www.news.com.au/national/saliva-test-with-87-per-
cen...](https://www.news.com.au/national/saliva-test-with-87-per-cent-success-
rate-to-bolster-victorian-war-on-
covid19/video/03cb674d50ace2fc30ef1a2a4a4a14fb)

~~~
coatmatter
87% sounds pretty good to me if it encourages a lot more people to get tested.
I do wonder how many are avoiding a test because the _know_ from others'
reports that it's most uncomfortable. Think about the number of people who are
afraid of simple medical procedures such as injections and apply that number
to those who don't wish to get "brain scraped". It's a problem.

------
gboss
I really do not understand what the hold up is. In California I know over ten
people whose results have taken more than seven or eight days to come back.
This is in the past two weeks. I am still waiting for my results from Sunday
six days ago. It really is inexcusable how mismanaged this epidemic is in the
United States.

~~~
MertsA
I live in Florida and was exposed to some respiratory illness with symptoms
consistent with Covid-19. As soon as I had symptoms I immediately did what I
could to get tested and specifically went for the fastest PCR test I could
find (I'm in between primary care providers, couldn't find a way to even try
to get a rapid test in my area). My insurance provider lists the only testing
location covered as an undisclosed drive through site located somewhere in a
city a good hour and a half drive away from me, with the second closest
location being a 2 hour drive. The county had a free testing event scheduled
for 2 days later but only had 400 tests, was first come first serve, and
explicitly stated that you couldn't line up before they started testing as
they literally weren't opening the gate to let traffic off of the street
before then. The county also listed a 10 day wait before test results would
even be available which is just flat out useless. Luckily the day before the
county testing event my wife managed to find free testing offered by Quest in
a somewhat nearby city that advertised that results would be available in 3-5
days instead of the 10 that the county claimed. I went there, got the nasal
swab done, filled out a bunch of forms with clipboards and pens that were
being reused with no sanitization between people, and signed up for Quest's
online accounts to get the results.

Today is literally the first day that I'm free from quarantine. Not because I
got my test results back, but because the latency in testing has gotten so
drawn out that even if that test eventually comes back positive, I already
meet the CDC guidelines for ending quarantine. That test was completely
useless for me and only serves to add some data to the statistics around the
pandemic. Right now, if you want to get tested and you're not a high priority
case (i.e. hospitalized), at least in my area, you can't even do that for all
practical purposes. It would be arguably better if they just randomly tested
only 50% and had a more reasonable backlog than testing 100% with a backlog so
long that all but the high priority tests are useless by the time the results
are available.

We've had literally months of time to ramp up testing nationwide. This
pandemic is far from over and it's already killed 145,000 Americans. This is
inexcusable incompetence by the legislative and executive branch.

~~~
manquer
I am not sure the delay is due to the backlog only .

There are only few locations that actually run the assays the logistics of
getting the sample to a location is significant. Not to mention regent and
other resource shortages mean some locations are off and can’t process anyone
. Your sample gets moved somewhere else

Also testing is many times done like binary searches. Some 96 samples are
combined and tested , if it is are negative no further tests required , if
they come positive breakdown and so on . While even in the worst case you may
will not need 96 separate tests, the steps are sequential, tests will take
more time if more people on average become positive.

------
latchkey
Israel is 30 seconds.

[https://hamodia.com/2020/06/30/israeli-company-introduces-
co...](https://hamodia.com/2020/06/30/israeli-company-introduces-coronavirus-
test-results-30-seconds/)

~~~
ergwwrt
How to learn more about this sensor?

------
x87678r
Emirates had something about 10 minute test back in April before boarding. I
never figured out how they did that.

[https://www.emirates.com/media-centre/emirates-becomes-
first...](https://www.emirates.com/media-centre/emirates-becomes-first-
airline-to-conduct-on-site-rapid-covid-19-tests-for-passengers/)

~~~
ianwalter
Not sure how they can do that but my company's device can do it in 20:
[https://www.forbes.com/sites/johncumbers/2020/07/01/a-new-20...](https://www.forbes.com/sites/johncumbers/2020/07/01/a-new-20-minute-
covid-19-test-will-use-crispr-gene-editing-technology-to-deliver-results-at-
the-doctors-office-supermarket-or-workplace/)

------
femto113
"Because no swabs are required, and no fancy equipment is needed, the tests
are less vulnerable to backlogs"

That, sadly, is nonsense unless you have thousands of technicians available to
process the tests. What we have here is a classic latency vs throughput
problem. 45 minutes to an answer is a lot better than 24-48 hours which is
about the best achievable with the PCR tests. But even if only a third of the
45 minutes is a tech messing with "pipettes, a heating source and an enzyme
mixture" and the rest is waiting for reactions at best one tech could do
perhaps 30 a day. On the other hand the "fancy equipment" in PCR labs can do
thousands of such tests in one go (UW Virology here in Seattle is doing over
5000/day[1]).

[1]
[http://depts.washington.edu/labmed/covid19/](http://depts.washington.edu/labmed/covid19/)

~~~
markus92
PCR test can be done in a few hours at most. It’s mostly the whole logistical
problem that takes time.

~~~
femto113
Yes, the time's not the test, it's getting the sample from where its collected
to the lab (e.g. a doctors office that may only get collected from once a
day), assembling a batch, running it, collating the results and sending them
back out. Any batch-oriented, industrial-scale testing operation will suffer
the same delays regardless of the actual process.

------
Jaxkr
I competed against this team in this year’s CU New Venture Challenge. They got
first, we ([https://docforge.dev](https://docforge.dev)) got second.

They are doing some amazing work with this and SickStick.

------
ergwwrt
This is still not a home test. Keep working..

~~~
uptown
This company claims to have a home testing kit:

[https://nanologix.com/](https://nanologix.com/)

[https://youtu.be/HVcSchmwXgc](https://youtu.be/HVcSchmwXgc)

------
the-dude
n=60, deactivated virus, no humans.

~~~
starpilot
less space than a nomad

~~~
yjftsjthsd-h
Yes, and we'll have fusion reactors, HIV vaccines, and a cure to cancer any
year now. Science is less subjective than consumer electronics.

------
nxpnsv
Antibody tests give similar results in 10min with a drop of blood.

~~~
amiga_500
But you have to wait longer for the antibodies to appear in the human.

~~~
nxpnsv
True, usecase perhaps is more to confirm that what you had was covid, kind of
complementary to this.

------
iandanforth
A virologist is quoted comparing the search for a corona virus vaccine to the
search for an HIV vaccine? Have I misread all the science over the last six
months? That seems like an absurd comparison.

~~~
bosswipe
Mind explaining why it's absurd?

~~~
iandanforth
They are very different and HIV is very nasty. As a retrovirus that targets
the immune systems (T-Cells, macrophages etc) with an unusually high genetic
variability it is really hard to reliably invoke the kind of immune response
that normal vaccines rely on for their efficacy. Corona virus on the other
hand is an RNA virus that mainly attacks the respiratory system and invokes a
strong (often too strong) immune response.

They just arn't very similar beasts, if you had to draw an analogy about the
difficulty of the problem it would be that we don't yet have a cure for the
common cold (which is a corona virus.)

~~~
josephcsible
> the common cold (which is a corona virus.)

A minority of them are. Most instances of the common cold are caused by
rhinoviruses.

------
Markoff
sound promising for air travel with 59/60 accuracy and last positive sample
inconclusive

