Beginner's Mind

#26: Science Explained - PCR Tests for Dummies

October 22, 2020 Christian Soschner Season 1 Episode 26
Beginner's Mind
#26: Science Explained - PCR Tests for Dummies
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Show Notes Transcript Chapter Markers

In this episode, I had the pleasure of talking with two Diagnostics Experts.

Irina Korschinek, CEO of Ingenetix and Albert Missbichler, Business Angel specialized in Diagnostics.

Do you want to know answers to all or one of the following questions?

• What is a PCR test?
• Why is it the gold standard for measuring SARS-Cov2 Infections?
• What does a positive or negative test result say?
• Why do false positives and false negatives exist. Shouldn`t the test have 100% accuracy?
• Why do no yes or no answers exist to a viral infection?
• What makes diagnostics so complex?

Speaker:
Albert Missbichler (https://www.linkedin.com/in/albert-missbichler-3a362931/
Christian Soschner (https://www.linkedin.com/in/christiansoschner/)
Irina Korschinek (https://www.linkedin.com/in/irina-korschineck-35a40289/)

Organizations:
CS Life Science Invest (https://lnkd.in/eyhWK7H)
Ingenetix (https://www.ingenetix.com/en/home/)
Fianostics (https://www.fianostics.at/en/home/)

Be part of our Network:
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0:00
welcome to a new episode of the life science get together top podcast today we are talking about one
0:06
of my favorite topics right now it's uh the pandemic sask of 2 has conquered the
0:12
world and it's really hard to say are we at the beginning midterm or the end of
0:20
the pandemic uh when we look at it like a soccer game it's difficult to say if it's is it half
0:27
time is it the beginning of the game or are we at the end the reliefing event
0:32
that politicians are seeing is the development of a vaccine
0:37
some say it should be on the market by the end of this year or early 2021
0:43
look at clinicaltrials.gov i see the endpoints of the studies in
0:50
2022 and in the meantime the politicians try
0:55
to find out to learn more and support the scientists to learn more about
1:01
the virus and one part that popped up very often in the news
1:08
is the diagnostics of the virus and with that the term pcr test
1:14
is frequently mentioned in the news and i was always wondering what
1:22
is this pcr test about and this was the reason to contact irina questionneck and
1:29
albert misspeekly and ask them are you willing and and happy to talk with me about pcr tests and
1:36
diagnostics around saskatchewan thank you thank you for introduction
1:43
thank you very much irina give us a little bit about your background
1:49
what is your daily business my daily basis working with dna and rna
1:56
[Laughter] so that my job is called i am a
2:02
molecular biologist yeah but in simple words it's really we just work with dna rna
What are you doing professionally
2:10
so it's basically exactly what we're talking about today and ariad what about you what are
2:17
you doing professionally i'm i'm now being a business angel and
2:22
my background my scientific background comes from clinical diagnostics i mean with immunoassays not rather dna
2:30
but rather protein the protein part of the diagnostics since about nearly 30 years
2:36
and it's very interesting to see that many that pcr tests have been developed
2:44
in the last decade to be very precise and very sensitive for a
2:50
numerous amount of diseases and then questions scientific questions so let's
What is a PCR
2:56
let's uh with that having said let's come to the to the first point what exactly is a pcr test
3:05
it's easy to explain first of all you need the sequence now that's very very
3:12
important especially when you think about corona virus two now we didn't had
3:19
half a sequence in the beginning of the year and then the chinese uh
3:25
published the sequence and this made it possible to design a pcr so you need the region
3:32
you have in in you have the whole virus gene genome for example and you choose a
3:39
region that's very very important because this region has to be very conserved
3:45
yeah then you define the borders of the region you would like to see and then
3:52
you copy it that's called amplification yeah and you copy and copy and copy
3:58
until you can see it yeah so you have to think like working with a camera
4:04
when you zoom in and you zoom in as long as you can focus uh to the object of interest
4:12
okay uh you said first you need the sequence so the first sequence came came from china was basically the
4:19
chinese scientists were the first one it's the international database okay and they put it on
4:25
and in the pcr test are you looking for the entire virus
4:31
genome or are you looking for you mentioned regions are you looking for pieces around it and who defines that
4:38
what what you should be looking for yeah you're looking for pieces yeah which are essential for the virus yeah
4:45
if they are get getting mutation and it in it would change
4:51
yeah so it's basically it is really a region you know a little bit more about
4:58
the virus you know maybe from from family of this virus that this is the region to bind to the human
5:05
receptor on the cell so may i should interrupt here another
What is a new virus
5:10
question you detect a new virus or uh it is named the new virus because it's a
5:17
new sequence so this sequence a little bit different to all the viruses known until now
5:24
coming from the antibody part of the diagnostics we all know that antibodies never are 100 specific but
5:31
always have some more or less amount of unspecificity the question now is for me
5:38
how do you define that the part of the rna you are copying is 100 specific for this virus
5:46
and does not detect rests or parts of any other virus that could be similar to
5:51
that okay because sask of 2 is not completely new
6:00
it is a virus species from a family
6:06
and for example sas one is well known and the chinese did a lot
6:14
of work in the last few years putting in a different sas sequences uh
6:21
so there were already 450 sequences in in the database from sas one or similar
6:27
sas uh the saskof2 was completely new
6:32
but um how is this called you you see that it is related here so
6:39
we align is it the word which yeah you can align the sequence
6:46
and you see that the cough two sequence aligned to sas one
6:51
sequence and then and sas one is not our problem in the moment
6:57
yeah because it's it's only gone yeah so we choose a region which is similar
7:04
to sas one so this means for me this is essential for the virus
7:10
this region yeah and the next step is that you have to look to other viruses
7:16
which you would would not like so they shouldn't be detected with the bcr that's very important yeah
7:23
so what kind of coronaviruses yeah like i don't ever convince this yeah
7:29
yeah so there are a lot of of uh pcrs uh um
7:35
available and they are based only on sas cov2 yeah and
7:42
this is you have to be careful with that because here you can't see if where you
7:48
don't know if it is a conserved region or not so they have to choose or they choose
7:54
uh two or three targets to be on the safe side okay and who defines these targets and
Who defines targets and regions
8:01
regions is this uh the lab doing that's doing the pcr test or
8:06
uh are these scientists on the universities uh who is who is uh bringing the
8:13
definition of regions and targets to the world both but let's see
8:22
some of the scientists hates it i love it it's a lot of work you have to be a
8:28
little bit a nerd because you have hundreds of sequences
8:33
in the database and you have to find the tree in the in the forest
8:39
yeah and there are some so sometimes i don't see the sequence
8:45
yeah you have to be really concentrated uh and working
8:50
two or three hours uh on the path also together and then you
8:56
have to start on the next day again to be on on the safe side yeah so
9:02
you have to be a specialist yeah and yeah you have to love it but yeah you in the meantime you have
9:08
more than uh i think it is 28 000 sequences of cof2 in the database
9:18
so 28 28 000. yeah it is called the geese eight database
9:24
it's a special database for influence and cos2 okay so basically you can make sure that
What to look for
9:30
when you are looking for the virals that you really are looking for south cook two and not any other coronal virus yeah
9:35
you can be sure but you you have to ask the bios if it is stays conserved in the switch
9:42
don't don't change don't mute it yeah please when i look at the workflow so
The workflow
9:49
you have the first part the virus is detected i think this is the basis that we can start pcr testing so
9:54
we must know the virus and the second thing is we must know the regions that we're
9:59
looking for and make sure that we don't start mix it up with other viruses so it would not make any sense
10:06
yes uh what comes after the workflow then you said uh you are looking basically you start
10:11
looking for the needle in the haystack so basically you are searching for the virus how does that work
10:19
yeah you have to take the right samples we begin with this yeah is it a sample
10:26
from the nose or for the mouth or uh from the blood yeah so sask of two it's
10:32
not in the blood world there's only a few days in the in the virus in the blood uh and it can be sometimes that it's
10:39
only in the faces yeah uh so that's very important and then it's an rna virus
10:47
it's not a dna mass it's rna virus yeah and rna virus is very very sensitive
10:53
or there we have there are a lot of enzymes around cutting the rna
11:00
yeah in a minute or two so the sample has to be stored correctly and what is
Storage
11:07
what is the correct storage of such a sample yeah for short time you can
11:14
leave it in water yeah but only one minute or two yeah and you can leave it in a salt
11:21
solution and it's very stable or you put it in the freezer but then you have
11:27
to be very careful but because you're destroying the the surface of the virus
11:32
and when you take the sample out of the freezer yeah the rna is free and it's not
11:38
protected anymore yeah and then you have to work immediately uh to get all the
11:46
enzymes which are destroying the rna out of of of your sample yeah that's a very
11:53
um yeah very interesting uh uh uh step in all this yeah because
12:00
um yeah there are a lot of mistakes what what what does it mean so let's uh let's plan for the worst case
Mistakes
12:07
let's say i would be the one who's taking the samples and have absolutely no idea how to handle that
12:13
so i mess up the rna of the virus what does it mean for the pcr test you
12:20
it's negative okay so yeah maybe it's it's okay the negative but
12:27
yeah you would not see that the the irony you can't amplify it yeah so that's a very
12:33
uh yeah special step for for the lab yeah and then everybody thinks that they can
12:39
leave it in minus 20 or minus 80 and then they forgot that they have to
12:44
work very very fast
Sample Preparation
12:50
so it's uh it needs specialists i guess to to do that so to take the samples and to
12:56
make sure that it really is stored in the right way so that when you get uh the samples
13:04
that they still have virus rna in it and it's not destroyed it really
13:10
starts from the beginning yeah you have to choose the right uh uh possibility to get this sample
13:18
yeah that's that's very important um and then how to store it how to
13:24
transport it to the lab it's the next step
13:30
and then of following the next step in the lab is uh to extract the rna
13:38
how are you doing that um you can bind it to a surface silicon surface yeah or you're
13:45
working with magnetic beads it's also binding to magnetic beads the first step
13:51
is the lysis path and lysis buffer is grenadine and
13:57
when you put in the guiding buffer then it's completely stable
14:02
yeah uh then you bind it and you wash it you push away all the the enzymes and salt what
14:08
is in your sample and then uh the last last step is dilution step
14:14
uh more or less you elude the rna because it's very uh easy to uh solve in uh
14:21
in in water you eluding in water and then you have to be careful
14:27
again why why because then the rna is again very
14:34
easy to destroy okay because if you don't have the right water
14:39
or uh we're not careful in contamination you're in rnase the enzymes are coupling the
14:46
rna again because we have it in in our sputum a lot of enzyme yeah for destroying the rna
14:53
uh yeah you have to store it exactly immediately in minus 20 or you have to
14:58
do the pcr and as i say don't touch it basically don't touch it
15:04
and then the actual begin yeah so coming back to the first step getting
15:10
the sample which we call sample preparation there are now now there's two two possibilities you
15:17
take these sticks these pads and then put some thing of the spoon out of the
15:24
nose and put it into some solution which is normally a salt solution or you have the goggling test which is
15:30
much easier and more convenient for the people are there any any experiences on
15:37
[Music] problems with getting the samples and transporting the samples
15:43
yeah gucking is is something what uh when you think about small children
15:49
yeah some of them they can't guide they are not used to it yeah so
15:58
yeah it was for me this was also strange there's somebody who can't do it but
16:03
yeah small children sometimes can't do it but when we stay at the sampling step i mean first when i read about the pcr
16:09
test i thought the throat or no smoke is something from here not really up why is it important to go
16:16
really the whole way so to give the patient or the the person the whole experience of the
16:22
nosemob from from the back why is that so important it is not
16:30
no it's it's depending uh how sensitive you want to work so if you really want to have see one or
16:37
ten copies of the vows yeah then yeah you have to find them
16:42
yeah but these are let's say normally when you
16:50
are you are sick or you are contaminated with the virus so you have
16:55
thousand millions of copies yeah and then you are a so-called spreader yeah
17:03
and there is also a diagnostic uh dark spot
17:10
yeah when the cells are you get the virus or you you're getting infected from the virus
17:16
then the virus is looking for the cells and they go into
17:21
the cell and then they are in the cells yeah and they may be a one day or two days in the
17:27
cells and then they go out of the cells yeah and this is the
17:33
time when you can detect it yeah and then you have at this stage you
17:40
have more than 100 500 000 copies already yeah so it's also depending on
17:47
your application what you want to do to to find is it some is it if somebody is infected
17:55
and there's already a spreader or uh so he can if he or he can infect
18:02
other people or you want to detect uh for a
18:08
theater or a sport event there for the next two hours
18:14
if you only want to see it can they all the people got get in because there shouldn't be any
18:20
spreader in in the theater uh then you don't need a high sensitivity
18:25
high sensitive test yeah but if you want uh to test when somebody wants to get
18:33
or they wait for vacation and they go to another country yeah you needed the tests more sensitive
18:42
because you don't know what is going on yeah but a lot of people they had cost to uh the cobit 19
18:49
already they have very low copy numbers for weeks or even months and
18:58
this is very important information for the report of the lab report yeah
19:06
because this be this guy is not infected anymore yeah when we look at the workflow
Workflow
19:14
and we start with the no swap how much time does it take uh until you start with the pcr testing
19:23
do we talk about 30 minutes half an hour okay so from the swap to the testing it's half an hour basically
19:29
the work is also there all the putting all the important things into the computer yeah
19:37
this is a lot of work and when you start looking for the sequences of the virus so
19:44
uh this is then basically the action that hap that's happening in the pcr test that
19:50
you compare the samples that you get and you make copies and you compare it to your library and say okay do i find
19:56
something that's similar so uh but basically you're not looking
20:02
for the entire virus for the entire genome so you're looking only for a little bit apart can
20:08
can the pcr test then distinguish between pieces of the virus or if there's
20:14
already entire virus in that if if you have pieces
20:20
of it it gets very very fast destroyed yeah so there is it it is
20:29
impossible to detect pieces because that yeah it is only for a minute in in the
20:35
body or in the in this booth okay so what does a positive or a
Positive or Negative
20:40
negative result really say when when the pcr test is finished so it's either it's binary i guess so it's either you
20:47
find the virus or you don't yeah so if if you find it it doesn't
20:53
mean that you're getting sick but you have it yeah
20:59
but let's say when you you find only 10 or 20 or 100 copies yeah um
21:07
so the virus is there yeah but you have an immune system we all have immune system
21:12
yeah we don't know what the immune system is doing yeah so if they immune systems recognize it as a
21:20
killer violence yeah it starts to uh to fight yeah and they well sometimes
21:27
the immune system is the winner and sometimes the virus is the winner so it doesn't mean that the person is uh
21:35
sick so basically whenever testosterone is coming and say it's positive it let's put it a little bit bluntly
21:42
it's not a death sentence right away so it's uh it's basically the question what's
21:47
happening in the body of the patient but definitely it is they have to stay
21:52
at home yeah and if yeah they think they are getting sick they have to be very very
21:59
careful yeah uh and the best thing would be to test the person again
22:05
after two or three days albert i think this is a very important part of
22:11
the discussion now because we always have a test result
22:16
positive or negative or it is it is reported positive or negative this is ridiculous yes exactly
22:24
i'm not a specialist but i i i know that the term of real-time pcr which
22:31
enables us to quantify at least to a little bit the amount of virus we
22:37
are the amount of rna we are detecting and i'm really angry now that people always
22:46
talk about positive tests if they are sensitive enough you will find the positive signal in a
22:52
huge amount of persons which are far away from being sick or even and more
22:58
more and more a way to be a spreader another um i think it should be focused and they
23:04
should be spreading to the public and to the public uh persons who are
23:10
responsible for our politic discussions that there should be
23:15
a difference between virus particles are detected
23:20
and and useful or a dangerous amount of various particles like the technology
Virus Detection
23:26
how can you how can you distinguish that in a pcr test so if it's just a virus detected or if it's uh dangerous
23:32
what's the values that you're trying to find or looking at can i explain it with a sample
23:41
yeah so if you think about a factory with 2 000 people yeah and your uh
23:50
yeah make a violence test with these people uh and you find one positive
23:57
with 50 or 100 copies uh in the bcr
24:04
then you should send this person home
24:09
but you have to do nothing in addition because he or she is
24:17
not infectious
24:22
if you get results with 1 000 1 million let's see 1000
24:29
you have to be careful in this in the yeah with the group of people
24:37
which were together with with this person yeah uh like the room
24:44
or the the restaurant or some in a seminar room you have to find out who was together
24:50
with this person and they should go home immediately and stay at home and then you have maybe
24:58
a result with one million of copies or even more yeah
25:03
then yeah you have to stop everything and you have to be really
25:09
really careful yeah you have to send everybody at home you have to clean everything
25:14
yeah okay you have to yeah do you have to lock down to shut down your whole
25:20
factory and that's very very important to know like
25:25
all the schools the thing the problem is as far as i get the news
25:30
the number of copies never is reported yes that's it's like for 20
25:37
25 years we had this yeah we put the things on there on a neato cellulose or
25:44
something or end points here we could say both a different negative yeah but we have a real-time instrument now
25:50
it's very uh expensive instrument yeah to get the copies out there and we
25:57
should use it is this this ct value
CT Value
26:03
so basically you can uh so one thing is no positive pcr
26:10
test is similar to another positive pcr test so they they are not the same uh
26:16
you have to look at the second level so if it's positive then you can with the pcr test you have
26:24
nowadays find out how many copies are in the sample and with that copies you can make
26:31
assumptions on the health status of uh no not health i wouldn't say health yeah
26:38
uh but yeah we don't know that because we most of the time we only see positive
26:45
and negative results yeah maybe yeah you are right we don't know it
26:50
yeah because we don't know if it is high copy or a low copy and the person is sick or not
26:57
yeah but that's the one to explain the cds here when i say copy yeah you you copy it uh
27:05
so you have 100 copies at the beginning maybe of the virus and then you make one amplification one
27:11
cycle in the pcr then you have 200 copies and you make another yeah then you have
27:17
400 copies yeah another exactly then you have 800 copies yeah and again and again and again yeah
27:24
and the see the point as of
27:29
the point when you see it and you can detect it in your instrument yeah that is called the cd yeah but it means
27:37
okay ct 10 means after 10 cycles yeah i could see that there's an
27:44
amplification that is supposed to be yeah then you have one one million 100 million of copies okay
27:52
so that's the ct value but it is not called cd anymore it is called c c and quantification coup
28:00
okay cool okay i think but i think ct value has hits the the the yeah they're using that quite
28:06
frequently so basically with a pcr test you theoretically have the potential
28:12
on one hand to find out whether a sample is positive or negative then you have the possibility to find
28:19
out how many cycles you need until you find a copy yes and on top of that the third part
28:25
you can find out is how many viruses are in the pcr sample generally but the only thing that
28:31
we are currently reporting is positive or negative so all the other values are not really reported we don't have to
28:37
report exact cd values here copy numbers here we have to think it's very high it's uh
28:44
uh under 20 cycles yeah or it is in the middle 25
28:52
oh it's very low yeah and it's 30 or what yeah so this would help yeah okay
28:58
and why does this not happen don't ask me
29:04
because this really is really causes economic problems yes because
29:10
everybody's frightened of a positive result which may mean after 38 cycles i find
29:17
two copies which means nothing in part of in sense of
29:22
illness now completely right yeah so it would be
False Positive
29:27
important to to report that to make sounds decisions i mean to make it a little bit more
29:32
complicated uh i will i want to to ask another question um when you hear testing you always
29:39
reminded uh school days 80s 90s early 90s and
29:45
in my school life it was binary it was either it was a positive or a negative
29:50
test result and i didn't really care if the grade of positivity um the only thing you cared about was
29:57
not to be negative um now when i hear the word pcr
30:03
test in the news i got confronted with false positive and false negative i mean
30:09
comparing that to my school life it was either positive or negative and they couldn't i mean i wanted to argue with the teacher and say
30:16
sorry but it's false negative actually it's positive but they were not very up to that what does false positive and false negative
30:23
mean uh in a pcr test why is that happening yeah uh you can have a sample with very
30:31
very high copy numbers that's mean one 100 million on copies and then
30:40
you can contaminate doing all the steps the extraction step when you set up the
30:45
bcr yeah you can contaminate other samples with it it's like like the person is spreading
30:54
yeah your sample is spreading yeah and uh but normally you have too much
31:01
positive results afterwards yeah and you see that there is one sample with very
31:07
very high copy numbers yeah and then you know immediately and you go back to the original sample and you have
31:14
to make everything again from the beginning on yeah but this can happen but
31:20
normally yeah you recognize that false positive um first negative
31:27
[Music] it's mainly because of
31:32
how you take the sample yeah that's the main reason yeah sometimes we get
31:39
i saw oh i get the information from the labs that they that
31:46
uh this stick yeah was completely dry so
31:52
there was nothing they didn't use to stick it so that something went wrong
31:59
okay so it still can be that if the sample is not taken in the in this example it's of course uh
32:06
but the test uh by itself when we assume that everything happens correctly uh is accurate so
32:13
by the test itself it's not that so it's it's the workflow behind it that causes this effect
32:18
yeah you have an in in inhibition control yeah you have a extraction control and
32:25
an inhibition pcr control also based on rna and this is your
32:34
information in in the reaction yeah this has to be uh always positive yeah and then you
32:41
know that nothing went wrong in your okay so it's it's basically in the in the workflow
32:48
it's the human error it's not the the testing error in the scientific era it's uh
32:53
basically how humans have handled the samples nowadays not only humans are working in
33:00
the lab there are a lot of instruments
33:06
also but good to know that also machines are human and make mistakes
Wrong Corner
33:15
uh i was always thinking when they heard false negative i had the picture in mind that it's like uh
33:20
being in a dark room uh what is what if the pcr test is looking in the wrong
33:25
corner while the virus is hiding away in a different corner is this also a possibility that you just
33:33
oversee the virus in a sample because it's you're not looking at the right spot in
33:38
the sample this is completely impossible no that's that's that's possible yeah of
33:43
course uh and [Music] yeah i think it you would recognize
33:52
in two or three days or four days yeah because some of the these people are sick yeah and then
33:59
yeah you immediately say okay what's going on we are facing this now in in
34:06
in the end of the year because it's normally the influencer season yeah and then there is also yeah
34:15
same respiratory symptoms yeah and this can be a little bit difficult
34:23
yeah then you say okay is this influenza you you're not searching why you don't do a pcr for influence anomaly
34:30
because everybody's involved with cough too uh but yes we have to look at that yeah very very
34:38
uh yeah focused on it what is going on this is it means influenza a b or is this is this cough
34:44
two we which is not detected anymore from the pcr yeah because we can't ask the bias yeah so i
34:51
mean normally sorry normally there is no pcr test on influenza viruses in the diagnostic
35:00
surroundings [Music]
35:06
yeah to see if it's going on or not yeah in every county has special uh labs who
35:13
are searching for respiratory disease to and they have to inform the european um
35:20
organization if if they see that influenza is is now raising
35:28
from the disease diagnostic from a diagnostic part of you um
35:34
influences detected or is diagnosed by symptoms
35:40
no no there are tests also pc artists yeah but this is simply
35:46
simply uh think of money and time yeah if if the pci is done with for influenza
35:54
a and b but i'm i'm sure we will uh yeah we will do pcrs in in in in the end
36:01
of the year also for influencer a and b to be on the safe side just to distinguish between
36:07
influencer and yeah yeah i hope so i read on the internet
Switzerland
36:12
that switzerland seems to go in a different direction um it was think two days ago when i read on
36:19
one website that the country doesn't want to distinguish between influenza and south
36:25
koftu anymore and it sounded to me like switzerland is just going to sum everything up on
36:32
the south too which is quite interesting because from what i got from the talk
36:38
is that a positive pcr test when it measures all values uh it still
36:44
doesn't feel to me like uh being a real substitute to a diagnosis by by a physician
36:53
so it's still recommended recommendable that a person with a positive pcr test
36:58
and all the information he got that he consults a doctor or do you see the pcr test really as a
37:04
substitute in the diagnostic so that we don't need the physician's opinion anymore
37:12
i think the physicians they can't say if it is influenza a or b or respiratory
37:19
cynical virus or para influence or whatever yeah we you really need to test
37:24
the pcr test to distinguish this and and if if if you go to the hospital as a
37:31
patient yeah uh you should go to the influence corner or the corona corner yeah they
37:38
shouldn't they shouldn't mix up i could agree with that so this is one thing to detect the virus so which virus
37:44
is it because it makes a difference then in the therapy so if it's influenza there so yeah
37:50
another therapy doesn't really make a difference in therapy i don't know
37:55
i thought i'm not quite sure because as far as i know there is no specific
38:01
therapy for influence a or b and so we don't have any specific therapy now for for sas curve two
38:07
so what all we are terrifying is trying to get the to keep the lung instead of the normal
38:14
function and to reduce the the process of infection
38:22
so from a therapeutic part of you i think we are far away from being able to have
38:29
specific therapies for a different virus infections but we can't but we can't
38:35
take the doctor out of the game i guess so it still needs the doctor to
38:40
recommend the right way of treatment either if it's uh if the person is healthy and can go
38:47
home and do nothing or if the person needs to be currentlined if the person needs to be in a hospital
38:52
hospitalized or needs to be in an icu i think that the doctor cannot be
38:58
completely taken out which sometimes i get the feeling when i look at the news that uh this is what we're trying to do
39:04
the pc has a help for the doctor and uh they need it for making their
39:10
decision yeah but it's only one part of it yeah
39:15
yes because the pcr number does not say anything about the health status of the person
39:20
it just gives you an indication of number of copies of of virus you have with yourself that
39:28
doesn't say anything about the status of your immune system but it can cope with this infection or
39:34
not because many people obviously have a very good immune system carrying the virus and
39:40
not being ill others have low corpus of viruses with a weak immune system why ever
39:46
and they're really getting sick and this never can replace so therefore
39:52
this pcr test or every every diagnostic test which
39:57
uh reports a number of whatever can replace the diagnosis of a medical doctor
40:03
no and then of course the treatment in the hospital is not always the same when it is cough too uh positive
40:10
the the person yeah so they they the doctor said this kind of treatment and this kind of
40:16
treatment this person needs yeah so it's not so simple yeah so there's another point that i
No Swapping
40:22
found really interesting in the last weeks um it's it's uh the
40:27
type of persons who need to get let's call it no swapped
40:34
usually in the past when i felt sick i called the doctor and he recommended
40:40
something mostly it will stay in bed and stay home you're young you will survive um events and stuff like that so
40:47
we all know that men suffer terribly from some viruses so we all
40:54
know the main flu all men and uh then i heard that uh healthy people
41:01
needs to get no swapped to detect the virus because they can be contagious
41:07
and on the other hand i read especially on facebook from friends that they were home with really severe
41:13
symptoms and they called this this 1450 i think is the number and i expected that when they call the
41:21
number and have symptoms that within half an hour uh the virus busters fly in and
41:27
make sure that the person is tested because for this person it really makes a difference the virus is detected or not and because
41:34
it's an important information for a doctor and then i heard from these people that sometimes it took
41:40
up to 10 days that somebody came by and i thought yeah well i mean if it's 10
41:46
days then everything is over anyways why does it take so long where is the limitation in the pcr test on the on the
41:52
timers because when it really takes uh 10 days for every person to get the
41:57
results when they are sick you don't need it anymore after 10 days
42:05
it's the cheap system you wait for 10 days and then
Why does it take so long
42:11
but why does it take so long that people are needs to wait 10 days from i mean first
42:16
that the people come and on the other hand then also that they get the test results in their hand
42:22
to be honest we were not prepared and we are not prepared yet now yeah we
42:28
need more people out yeah taking the samples uh
42:33
also the i.t system was not up to date and now we are focusing in
42:40
you know we are getting another problem is that the world is running out of simple
42:47
sticks or plastic tubes really yes
42:53
i wouldn't mind so i mean the idea of getting a no swap is not very appealing to me but but why is
Other options
43:02
still i mean we are now eight months in the pandemic and i think we have diagnostics experts who are doing
43:07
research are the other options on the market or coming to the markets than a pcr test
43:14
to diagnose or to defend the virus or is it the only gold standard of diagnostics that
43:21
we have um that will stick around for the next couple of years what's your opinion we have we have the
43:27
antigen test with they are they say they are
43:33
sensitive yeah i think it's not they are not so sensitive yeah but it's very fast
43:40
easy method it is cheap yeah and it is a method also to say
43:47
uh okay i don't have it in that with this that high copy numbers
43:52
uh so i am not uh dangerous in the moment than for the next two six hours yeah that's that's a good
43:59
system uh the problem is there's sometimes is it's false positive
44:04
with the entity and dust and and i don't know how to react with such
44:12
results if i tell you you are positive
44:18
yeah it's not a very good feeling huh in school it would be a
44:25
good feeling i said i said i shall hurt it yeah
44:32
general difference is with the antigen dust you really detect the part of the functional
44:39
virus so you can be sure you have an active virus no within your body no you can have the protein like rna
44:49
parts you can also have protein parts of the vowels yeah sure but it's not very yeah but i agree
44:55
with you it's it's not that sensitive it cannot be that sensitive normally and we have at least two or three
45:01
different antigens that are just detected nowadays i'm not sure about the specificity of these
45:08
but i think it could be a first shot to find out those people who are highly
45:13
infected because these definitely will be found because the sensibility and very fast
45:19
and with very low cost it can be done everywhere it can't be done in the front of a stadium
45:25
yeah and you don't need an expert you don't need instruments yeah
45:32
how quick is this test so this is a minute 10 15 minutes normally and what do you
45:37
need to what do you need to take the test the same species other the same samples
45:44
from the nose yeah no it's it's like the the proteins around the rna yeah
45:51
and then there's a surface of course yeah uh but yeah they stick together the irony
45:58
and the the proteins stick together yeah so you can take the protein from the virus or
46:03
you can take the rna from the mice okay yeah but we don't but we don't spare the nose swabs
46:09
no not really or you do the garlic test yeah as the home force i don't like the
46:17
idea i just stay home
46:22
but there is there's no there's no option that's for example you you take a blood sample or you just
Blood test
46:28
take it from like implants it's only yeah they don't go into the
46:34
the blood they stay in the respiratory yeah sometimes they go into the blood yeah
46:40
but only for a few days or hours with the blood test you can detect the
46:46
reaction of the of the immune system yeah you can look at the antibodies
46:53
so you can detect whether you have been infected with this virus and the immune system has reacted and if
46:58
the immune system has reacted and you have a useful amount of antibodies you can be
47:03
sure to be rather immune to the next infection for the next at least few months the
47:10
it is not known how long can immunization
47:15
last with this yeah there's a window for the antibodies to detect yeah because
47:21
the the b cells producing the antibodies uh they are only they if they are needed
47:30
yeah sure and then they go back in the holes and waiting for the next
47:36
infection and they're getting activated again and therefore you
47:41
don't find antibodies after a few months in in the blood yeah
47:48
anymore so basically with the current tests that we have on
Current tests
47:53
the market it means for detecting immediate infections we rely on
47:59
bcr test surrounding gene tests which basically is the same method of extracting the virus it doesn't make
48:06
a difference the only thing is the time so it's quicker the second test is quicker than the first one because of
48:11
the workflow it's easier to do and cheaper much cheaper much
48:16
cheaper yeah and taking any blood samples with this coronavirus doesn't make any sense because it's just for the
48:23
aftermath so you can say okay i mean there was an immune reaction and the patient is is healthy but it doesn't help to find
48:30
this asymptomatic patients that the governments are fearing right now that's their people without
48:36
symptoms who are spreading the virus because they don't stay home um i was hoping that anything was coming
48:42
to the market like i mean i like i like emperor i like apple watches so they can do a lot of things uh are
Digital detection
48:49
you aware of any digital detection system so that we can uh look at blood pressure or uh
48:55
yeah yeah yeah that's a good thing yeah they're very cheap them uh
49:02
they measure the the oxygen in the blood you know what i mean this is i say
49:07
always crocodile and they are cheap you can buy yeah with
49:13
20 maybe 30 are you yeah and yeah i would have one at home because you you see
49:20
immediately indeed immediately that in a lot of cases with kofta too that the oxygen in the blood goes
49:27
down yeah and this is not seen with influenza a or b okay so that's really a good test
49:35
for yourself yeah it's not 100 it's a 100 reliable yeah
49:42
but if if you have low oxygen yeah then your alarms should go on
49:49
[Music] this test is not validated until now
49:56
because um you should establish your your own normal value of oxygen saturation
50:04
and if you do that regularly like doing the blood pressure measurement everybody is in his normal range and if
50:10
this goes out of the normal range you should be alerted yes so this could be a very
50:15
very cheap and easy method for self-evaluation of
50:22
healthiness yeah i think it's not always the case that you have low oxygen even you have a lot of virus
50:28
already yeah uh and you don't know how how many wires you have here
50:33
uh but this is definitely yeah you it's a help yeah
50:42
um maybe not for smokers i read that uh people who smoked a cigarette also
50:47
sometimes experience the same problem that the oxygen level goes down in the blood but they have a different normal value
50:55
if they are infected with the virus it will go even lower okay yeah or you don't when you don't
51:02
smell anything anymore yeah yeah it's the second possibility
51:07
you have to say ooh something is going on okay this means i'm healthy because uh
51:16
it's very very good um but but this is still a complex test so
Reliable tests
51:22
i mean you said the oxygen test is not very reliable and the pcr test and antibody tests need
51:30
specialists uh so there is nothing coming so that that i can buy it people or
51:36
dm with hundred percent reliability uh to make sure that when i want to fly
51:41
somewhere that uh i can present a cheap easy hundred percent a current
51:47
test uh to to foreign governments um that doesn't need a lot of
51:52
specialists in the in the workflow you choose to fly somewhere now
51:59
uh you need a a good test yeah that's very important
52:06
yeah but if you would like to screen a lot of people
52:12
like all this uh children in school yeah we definitely need a cheaper test and an easier test
52:19
[Music] but this is yeah we have a lot of regulation
52:25
in the european union and the high we have high quality tests around there
52:31
because we have this regulation but we have to think now in a different way
52:38
and we have to develop cheaper and easier tests which are not so reliable yeah but
52:46
yes and fast yeah but for screening cleaning yeah where we don't need all
52:53
the tubes and pipette tips and instruments and plastic yeah i mean
52:58
what what worries me is with this live screenings it looks to me like um a lot of healthy people are tested
53:05
which is good so they can be sure that they are not sick and don't have the virus but on the
53:10
other hand sometimes especially with those friends who are at home alone sick and they don't get a
53:15
test it looks for to me that we use the resources yes and people with the problem
Conclusion
53:22
don't have resources available but for they for those people it would really make a difference so i think this should be something that
53:29
should be changed on the political level yeah yeah we have to be careful with our
53:35
resources yeah because we we need them for a longer time yeah and we need them for really having
53:44
any cases yeah yeah sometimes the doctor already know
53:49
that it is cov2 they make a test
53:55
you don't never need a test with a person with symptoms you have special symptoms
54:04
yeah and we don't have to repeat this test for them yeah they repeat it and repeat it and repeat that yeah
54:11
yeah if they're healthy afterwards yeah you don't need the test anymore they should stay a little bit more
54:16
at home be careful but yeah thank you very much for for talking with
54:24
me about this pcr tests it helped me to understand better what's
54:30
going on how i carried it as this and what it can be used for i hope we get
54:35
some new diagnostic methods on the market and i wish you a very
54:42
nice friday afternoon and weekend and let's stay in touch okay have a
54:49
great day again ciao thank you very much thank you
54:54
bye thanks for listening please please share the podcast and make sure you have subscribed have a
55:01
great day



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(Cont.) #26: Science Explained - PCR Tests for Dummies