Thailand Pass RT-PCR test v PCR test

[RandolphGB]

Thailand Pass requires an RT-PCR test. How is this different from a PCR test? 

 

Heathrow Airport has PCR tests in terminal 2 and terminal 5 with results available within three hours. Are these accepted for Thailand Pass? (https://www.heathrow.com/at-the-airport/fly-safe/covid-19-test)

 

 

[Lee4Life]

I came in on a COE, but was also required to do the RT-PCR test. I researched the differences between the RT-PCR test and the PCR test, and the differences are quite complicated, the description was far beyond my ability to understand. I had a hard time finding somewhere to get the RT-PCR test done and had to make a three hour round trip drive to a Lab that performed it. The technician who took the sample told me that the RT-PCR test was much more accurate.

     The following is only the beginning of the explanation I found:

 

Quote

Reverse transcription PCR, or RT-PCR, allows the use of RNA as a template. An additional step allows the detection and amplification of RNA. The RNA is reverse transcribed into complementary DNA (cDNA), using reverse transcriptase. The quality and purity of the RNA template is essential for the success of RT-PCR. The first step of RT-PCR is the synthesis of a DNA/RNA hybrid.

 

[partington]

1 hour ago, Lee4Life said:

I came in on a COE, but was also required to do the RT-PCR test. I researched the differences between the RT-PCR test and the PCR test, and the differences are quite complicated, the description was far beyond my ability to understand. I had a hard time finding somewhere to get the RT-PCR test done and had to make a three hour round trip drive to a Lab that performed it. The technician who took the sample told me that the RT-PCR test was much more accurate.

     The following is only the beginning of the explanation I found:

 

 

The technician was telling you slightly dodgy facts or didn't understand himself. It is not a fact that RT-PCR tests are "more accurate", it is actually that no other type of PCR test for Covid exists.

 

There is no such thing as a Covid PCR test that is not an RT-PCR test: ALL Covid PCR tests are RT-PCR tests, whether they are directly stated to be or not. (You can refer to the Covid test as a "PCR test", because an RT-PCR test is a type of PCR test, just as you can call a diesel car "a car" or a "diesel car" because a diesel car is a type of car.)

 

The exact technical details don't matter much, as the explanation is quite simple. Here it is:

 

PCR tests can only be done on the genetic material called DNA.  The Covid virus genetic material is not DNA, it is RNA, therefore before the PCR test is performed the RNA must be converted to DNA.

 

The enzyme reverse transcriptase (RT) converts RNA into DNA. Therefore an RT step to convert virus RNA to DNA must ALWAYS be done before doing the PCR step.  

 

Consequently ALL Covid PCR tests must be RT-PCR tests, or they simply wouldn't work.

 

Edited November 9, 2021 by partington

[partington]

7 hours ago, RandolphGB said:

Heathrow Airport has PCR tests in terminal 2 and terminal 5 with results available within three hours. Are these accepted for Thailand Pass? (https://www.heathrow.com/at-the-airport/fly-safe/covid-19-test)

 

 

This link you provide doesn't refer to any kind of  PCR test at all, but to a lateral flow antigen test, which is an antibody test.

 

 It is completely unrelated to PCR, but detects virus proteins on a strip. It wouldn't qualify where PCR tests are specifically required.

 

Edited November 9, 2021 by partington

[stubuzz]

I posted a similar question.

https://aseannow.com/topic/1238760-does-the-covid-test-have-to-say-rt/

 

[TorquayFan]

I boarded Finnair on Nov 4th and at check-in, they searched for the 'rt' prefix. The sweat started to gather on my brow. Sure enough, it was there. I'm not technical but I think it's just terminology ? i.e. the correct designation for any PCR test. I'd guess the tests given at LHR would comply.

 

i was told that the Airlines had been instructed by the Thai 'authorities' that it was requirement to board.

 

[partington]

11 minutes ago, TorquayFan said:

I boarded Finnair on Nov 4th and at check-in, they searched for the 'rt' prefix. The sweat started to gather on my brow. Sure enough, it was there. I'm not technical but I think it's just terminology ? i.e. the correct designation for any PCR test. I'd guess the tests given at LHR would comply.

 

i was told that the Airlines had been instructed by the Thai 'authorities' that it was requirement to board.

 

The LHR tests linked in the OP,  as I just posted (!) are not PCR tests of any kind, they are antibody tests and do not qualify if PCR tests are specified.

 

Also, as I just posted (!!), all Covid PCR tests must by necessity be RT-PCR tests whether stated directly or not, as there is no other kind of PCR test that works for Covid testing. I guess proper training would be needed for airline personnel to be made aware of this.

Edited November 9, 2021 by partington

[TorquayFan]

OK Partington. Sorry I was trying to deal with the terminology - I didn't check that link. But surely PCR tests were available at LHR and other airports. In my run-up I'd got the clear impression they were but maybe in a 'day before' context or there being a long pre-flight wait for the processing of results.

 

So - all PCR tests are rt-PCR tests. The papers have to say that.

[Lemsta69]

3 hours ago, partington said:

The LHR tests linked in the OP,  as I just posted (!) are not PCR tests of any kind, they are antibody tests and do not qualify if PCR tests are specified.

 

Also, as I just posted (!!), all Covid PCR tests must by necessity be RT-PCR tests whether stated directly or not, as there is no other kind of PCR test that works for Covid testing. I guess proper training would be needed for airline personnel to be made aware of this.

thanks for explaining all of this as I was wondering about it myself. it would a hell of a lot easier and less confusing if everyone just used the term "RT-PCR". average Joes like me don't really care about all the technical ins and outs when we're trying to arrange the right test.

 

if you click on the "Rest of World" tab it lists a "PCR" test. sounds like someone in Heathrow is being just a little too clever. 

[partington]

8 hours ago, TorquayFan said:

 

 

So - all PCR tests are rt-PCR tests. The papers have to say that.

Not strictly true - all PCR tests for Covid  are RT-PCR tests.

 

Other kinds of virus, for example,  have DNA not RNA as their genetic material (unlike the Covid virus) , so no RT step is needed to convert RNA to DNA, because it is already DNA.

 

Test for these viruses would NOT be RT-PCR tests.

[partington]

4 hours ago, Lemsta69 said:

 

 

if you click on the "Rest of World" tab it lists a "PCR" test. sounds like someone in Heathrow is being just a little too clever. 

Fair enough- I didn't click on that- however these are all "results next day" tests.

The OP referred to the "results in 3 hours" tests as  PCR tests, which is definitely not the case.

[Lemsta69]

26 minutes ago, partington said:

Fair enough- I didn't click on that- however these are all "results next day" tests.

The OP referred to the "results in 3 hours" tests as  PCR tests, which is definitely not the case.

oh sorry mate I didn't look too closely at it, I was fixated on this "PCR = RT-PCR if Covid-19" concept. just imagining the Benny Hill-esque shenanigans at the airport when you try to explain that to the check-in agent. that's everyone chasing each other around in circles for all the young 'uns on here ????

Edited November 9, 2021 by Lemsta69

[TorquayFan]

Thanks Partington - you know your stuff on this topic.

 

So all PCR tests for Covid are rt-PCR - Thailand's instruction to Airlines that the superfluous but accurate full technical description must be used, is not really very helpful to the average traveler. BFN

[captnhoy]

2 hours ago, TorquayFan said:

Thanks Partington - you know your stuff on this topic.

 

So all PCR tests for Covid are rt-PCR - Thailand's instruction to Airlines that the superfluous but accurate full technical description must be used, is not really very helpful to the average traveler. BFN

BFN? I know BFD what is BFN?

[RandolphGB]

14 hours ago, partington said:

This link you provide doesn't refer to any kind of  PCR test at all, but to a lateral flow antigen test, which is an antibody test.

 

 It is completely unrelated to PCR, but detects virus proteins on a strip. It wouldn't qualify where PCR tests are specifically required.

 

If you click on the table showing the options for departures it has PCR tests listed.

 

 

[partington]

2 hours ago, RandolphGB said:

If you click on the table showing the options for departures it has PCR tests listed.

 

 

 

Fair enough: I didn't click on other sections of that page, as I said above, so didn't see this, I just followed your original link.

[The Theory]

And what type of test will be at "one night" hotel on arrival ?

[Sheryl]

14 hours ago, partington said:

The LHR tests linked in the OP,  as I just posted (!) are not PCR tests of any kind, they are antibody tests and do not qualify if PCR tests are specified.

 

Also, as I just posted (!!), all Covid PCR tests must by necessity be RT-PCR tests whether stated directly or not, as there is no other kind of PCR test that works for Covid testing. I guess proper training would be needed for airline personnel to be made aware of this.

Correct except that the LHR tests are not antibody tests, they are antigen tests.  Still not acceptable where a PCR is required, of course

[richard_smith237]

3 minutes ago, Sheryl said:

15 hours ago, partington said:

The LHR tests linked in the OP,  as I just posted (!) are not PCR tests of any kind, they are antibody tests and do not qualify if PCR tests are specified.

 

Also, as I just posted (!!), all Covid PCR tests must by necessity be RT-PCR tests whether stated directly or not, as there is no other kind of PCR test that works for Covid testing. I guess proper training would be needed for airline personnel to be made aware of this.

Expand  

Correct except that the LHR tests are not antibody tests, they are antigen tests.  Still not acceptable where a PCR is required, of course

 

For the purposes of information (rather than contradiction).

 

Randox Carries out RT-PCR testing very close to Heathrow T 1, 2, 3 (at the Radisson Blu hotel) and other airports and key locations around the UK., they also do ‘home delivery, self swab PCR tests that can be ‘dropped off’ (at select locations) with results received the following day. 

 

https://www.randoxhealth.com

 

[chilli42]

Wow, I am impressed.  I would not have guessed anyone would have noticed or cared about what variant of Covid test they had.  Well done!

[partington]

8 hours ago, Sheryl said:

Correct except that the LHR tests are not antibody tests, they are antigen tests.  Still not acceptable where a PCR is required, of course

Absolutely correct!  I used language too loosely here, intending to indicate that the test was based on detection by antibodies rather than detection by PCR.

 

 

[stubuzz]

Will this be accepted?

 

[Letseng]

18 hours ago, partington said:

Fair enough- I didn't click on that- however these are all "results next day" tests.

The OP referred to the "results in 3 hours" tests as  PCR tests, which is definitely not the case.

You can get RT-PCR tests within 1 hr. Difference is the price because it gets priority processing. Just booked one at MUC airport. 

24hr one costs 69€, 1hr is 239€.

[partington]

9 hours ago, Letseng said:

You can get RT-PCR tests within 1 hr. Difference is the price because it gets priority processing. Just booked one at MUC airport. 

24hr one costs 69€, 1hr is 239€.

Amazing but true...the technology seems to be improving month by month rather than year by year!

!

[CoolNYC]

I had the same confusion since my uncle COVID result doesn't say RT-PCR and only say PCR. I even looked up FDA document on the machine that use to perform COVID test and it is using RT-PCR method.

 

I also called NY Thai Consulate and they confirmed that PCR and RT-PCR is the same thing and won't have any issue. I hope this is true. Will find out tomorrow if my uncle able to board the plane.

[BritTim]

10 hours ago, Letseng said:

You can get RT-PCR tests within 1 hr. Difference is the price because it gets priority processing. Just booked one at MUC airport. 

24hr one costs 69€, 1hr is 239€.

The difference in price is not just because you are going to the front of the queue. The machines that facilitate very rapid PCR tests are extremely expensive. No lab can afford to buy many of them. You are paying for access to this very expensive latest technology.

[Sheryl]

22 hours ago, stubuzz said:

Will this be accepted?

 

It should be but the lack of "RT" appearing in it could cause problems. Airline staff will look specifically for RT-PCR since those are their instructions and they are not in a position to know that all COVID PCRs are RT-PCR.

[richard_smith237]

20 hours ago, Sheryl said:

It should be but the lack of "RT" appearing in it could cause problems. Airline staff will look specifically for RT-PCR since those are their instructions and they are not in a position to know that all COVID PCRs are RT-PCR.

 

With each and every RT-PCR test certificate I have received I have looked to check that it actually states RT-PCR, they all have, but I’ve been prepared to edit the certificate to add in RT- before PCR.

 

Its the only way to avoid the hassles a lack of intelligent discretion creates. 

Edited November 12, 2021 by richard_smith237