Pre Cruise Testing and "False Positives"

[K_e_short]

I have been reading most of the comments and questions regarding the changes Carnival made regarding pre cruise testing.

 

I keep reading so many people saying "false positives".

 

Has anyone thought that perhaps if they test positive they actually have Covid?

 

That is why testing is required before you cruise now. To prevent people who have Covid from getting on a cruise ship.

 

You can have Covid with no symptoms at all, children especially.

 

I completely agree the frustration on changes, added costs, stress, etc. I get it. My December cruise is up in the air until they make a decision about December.

 

Perhaps realizing that testing positive means you have Covid and getting on a cruise ship and infecting others (vaccinated or unvaccinated) is very selfish.

 

(Oh and I'm not interested in hearing the stats on false positives. Get a second test if you want. Just bringing up an important point).

[lookitsmikel]

This is a pretty simple one.... If you are vaccinated make sure you go get tested 3 days prior if you are getting the antigen test, this is the one with the high false positive rate. If it is positive, get the PCR test to verify it (as many testing centers would do anyways). PCR tests can take a couple days, but they have a very low false positive rate. If both are positive, guess what...  You have COVID 😄

[audcc77]

I was a little nervous about this. We’re driving 8 hours to the port so we’ll test beforehand.
 

I  told my DH about the possibility of having to test and having to wear a mask by the time January is here. 
 

Amazingly, his response was “That’s fine.”   
 

Maybe he wasn’t listening to me because he’s not really a fan of cruising and his eyes glaze over when I speak about it.  🤔

[alyssamma]

31 minutes ago, K_e_short said:

I have been reading most of the comments and questions regarding the changes Carnival made regarding pre cruise testing.

 

I keep reading so many people saying "false positives".

 

Has anyone thought that perhaps if they test positive they actually have Covid?

 

That is why testing is required before you cruise now. To prevent people who have Covid from getting on a cruise ship.

 

You can have Covid with no symptoms at all, children especially.

 

I completely agree the frustration on changes, added costs, stress, etc. I get it. My December cruise is up in the air until they make a decision about December.

 

Perhaps realizing that testing positive means you have Covid and getting on a cruise ship and infecting others (vaccinated or unvaccinated) is very selfish.

 

(Oh and I'm not interested in hearing the stats on false positives. Get a second test if you want. Just bringing up an important point).

I thought they were good at giving false *negatives*...everything I've read shows about a 0.4% chance of false positive.

 

Sorry, to be clear, I'm saying I agree with the OP...if you test positive, it most likely isn't a false positive...you have Covid. It's much more likely, tho, that you have covid and test negative...which is, unfortunately, bad 😞

 

Edited August 7, 2021 by alyssamma

[K_e_short]

15 minutes ago, lookitsmikel said:

This is a pretty simple one.... If you are vaccinated make sure you go get tested 3 days prior if you are getting the antigen test, this is the one with the high false positive rate. If it is positive, get the PCR test to verify it (as many testing centers would do anyways). PCR tests can take a couple days, but they have a very low false positive rate. If both are positive, guess what...  You have COVID 😄

 

Has anything about cruising during Covid been simple? 🙂

[Jasonsterling]

7 minutes ago, alyssamma said:

I thought they were good at giving false *negatives*...everything I've read shows about a 0.4% chance of false positive.

 

Sorry, to be clear, I'm saying I agree with the OP...if you test positive, it most likely isn't a false positive...you have Covid. It's much more likely, tho, that you have covid and test negative...which is, unfortunately, bad 😞

 

I agree- I've heard antigen typically gives false negative more than false positives and that's why unvaccinated passengers have to do the longer PCR test because it has less false negatives, lol. It's still possible to get a false positive with antigen and I don't blame anyone having anxiety over the issue. A lot of people will not get results until they are already bound for the port and then they have loss money and time and extra frustration. Not too mention that the chances of a positive completely asymptomatic person infecting others especially when wearing masks or outside is extremely low. I'm really no more concerned with boarding a cruise ship in that situation then going to my local 7-11. I don't think people are selfish either, they are tired of everything that the pass year and a half has brought them. They are exhausted and there's nothing wrong with that. They have every reason to be.  

[tallnthensome]

1 hour ago, K_e_short said:

IPerhaps realizing that testing positive means you have Covid and getting on a cruise ship and infecting others (vaccinated or unvaccinated) is very selfish.

 

 

How would you get on with a positive test anyhow? 

[alyssamma]

2 minutes ago, tallnthensome said:

How would you get on with a positive test anyhow? 

I think the OP meant *not* getting a test and then getting on the ship when you're positive is selfish.

 

Or, not wanted to be tested to ensure you aren't positive is selfish.

 

[K_e_short]

18 minutes ago, tallnthensome said:

How would you get on with a positive test anyhow? 

 

Well it sounds like many people don't want to get tested for fear of testing positive. They just want to get on a cruise ship without testing, and thus maybe be positive and infecting others.

 

Your statement is exactly why I agree with everyone getting tested - you can't get on a cruise ship with a positive test.

[TooManyWakeUpsTilWeSail]

2 hours ago, lookitsmikel said:

This is a pretty simple one.... If you are vaccinated make sure you go get tested 3 days prior if you are getting the antigen test, this is the one with the high false positive rate. If it is positive, get the PCR test to verify it (as many testing centers would do anyways). PCR tests can take a couple days, but they have a very low false positive rate. If both are positive, guess what...  You have COVID 😄

Assuming my insurance covers BOTH, my plan is to go to the local Walgreens (literally walking distance from home) and get a PCR test exactly 72 hours before my cruise.  While waiting for results I will have an appointment near the airport (unfortunately no rapid tests near my home) at a CVS that offers the rapid antigen test; will only take the rapid if results from the PCR are not back yet.  Worst ethical concern is getting positive rapid and negative PCR.  Obviously positive both means I stay home.  Sigh

 

Edit to say for the record: I’ve been covid tested twice ever-last December I did have covid.  A couple of months later I was mandated by work to get re-tested as I have developed some post-covid lung issues (constant congestion, sinus infection).  I think I’m over that health hump for now after 4 doctor’s visits & I do not advocate abusing the testing system.

Edited August 7, 2021 by TooManyWakeUpsTilWeSail

[ChrisNCruiser]

1 hour ago, alyssamma said:

I thought they were good at giving false *negatives*...everything I've read shows about a 0.4% chance of false positive.

 

Sorry, to be clear, I'm saying I agree with the OP...if you test positive, it most likely isn't a false positive...you have Covid. It's much more likely, tho, that you have covid and test negative...which is, unfortunately, bad 😞

 

yesterday we picked up a BinaxNOW home antigen test from Sam's Club; the instructions agree with this - false positives are unlikely, but false negatives are possible. (We're hoping to go on the Magic on August 21st and wanted to see if we have anything to worry about now - we both came up Negative, so we plan to be super-duper careful between now and our scheduled CVS Antigen tests on the 18th.)

[Fla Mike]

13 minutes ago, TooManyWakeUpsTilWeSail said:

get a PCR test exactly 72 hours before my cruise

 It is my understanding, that Carnival is using "3 days" for testing instead of 72 hours, so your timing need not be so critical.

 Anyway, we have also opted for the pcr test due to the false positive results of the rapid.

In my area, at least, Quest Diagnostics is taking appointments for testing 2 months out. I was able to book my test for our late Sept cruise Thursday

 

.

 

[beloum]

Why can't Carnival test everyone at the port?    On my MSC cruise last week, everyone was tested at embarkation at the expense of MSC.  Sure it slowed things down, but was a lot less stressful then having to scramble to find one while travelling.  

[BohJang]

6 hours ago, Jasonsterling said:

I agree- I've heard antigen typically gives false negative more than false positives and that's why unvaccinated passengers have to do the longer PCR test because it has less false negatives, lol. It's still possible to get a false positive with antigen and I don't blame anyone having anxiety over the issue. A lot of people will not get results until they are already bound for the port and then they have loss money and time and extra frustration. Not too mention that the chances of a positive completely asymptomatic person infecting others especially when wearing masks or outside is extremely low. I'm really no more concerned with boarding a cruise ship in that situation then going to my local 7-11. I don't think people are selfish either, they are tired of everything that the pass year and a half has brought them. They are exhausted and there's nothing wrong with that. They have every reason to be.  

Thank you for your common sense reply.  I don't need to lose money and time and be anymore frustrated than I already am.  That is why I'm cancelling my November cruise.

[K_e_short]

2 hours ago, beloum said:

Why can't Carnival test everyone at the port?    On my MSC cruise last week, everyone was tested at embarkation at the expense of MSC.  Sure it slowed things down, but was a lot less stressful then having to scramble to find one while travelling.  

 

Completely agree.

Carnival has always been the 'discount" cruiseline of sorts. Other cruiseline have paid for things that Carnival does not. They could also test at the port and charge. I'm sure many would feel o.k. with paying for the test if the convinience of the test existed.

[Earthworm Jim]

8 hours ago, K_e_short said:

I keep reading so many people saying "false positives".

 

Has anyone thought that perhaps if they test positive they actually have Covid?

 

 

I don't get your point. That if you have a positive Covid test you might actually have Covid? Gee thanks, that thought never would have occurred to us.

[K_e_short]

22 minutes ago, Earthworm Jim said:

 

I don't get your point. That if you have a positive Covid test you might actually have Covid? Gee thanks, that thought never would have occurred to us.

My point is that we all want cruising to return yet I keep hearing people here worrying about false positives and then others are suggesting how to get multiple tests to confirm.

 

Why are people so shocked that they could get Covid? Why do some people not want to get tested for fear of testing positive (pre or post cruise)?

 

We are still in a pandemic and the best way to get back to cruising is to make sure that Covid doesn't get on the ships. The best way to do that is to test everyone.

[topaz123]

Local pharmacist, says of all the Covid tests, the Antigen is the least reliable. OH MY.....more drama I don't need.

[TooManyWakeUpsTilWeSail]

14 minutes ago, K_e_short said:

 Why do some people not want to get tested for fear of testing positive (pre or post cruise)?

People are fearing (probably not the right word) a false positive.  People are fearing (I am) not being able to get tested and get results in 72 hours (rural folks, folks traveling). People are put off (me! me!) that Carnival is forcing us to take a specific test at a certified facility when it would be soooo much easier for them to test everyone at port before cruising.  I’ve got a $20 in my pocket to cover the cost.  Hope that helps.

[K_e_short]

26 minutes ago, topaz123 said:

Local pharmacist, says of all the Covid tests, the Antigen is the least reliable. OH MY.....more drama I don't need.

 

I think we all agree that the decisions that Carnival have made regarding tests and the type of test makes no sense.

 

I am not ignoring the stress and annoyance all of this has caused people.

 

If I cruise in December I will get my son a pcr test as well (i have to get one anyways since I'm supposedly unvaccinated).

 

[Earthworm Jim]

16 hours ago, K_e_short said:

My point is that we all want cruising to return yet I keep hearing people here worrying about false positives and then others are suggesting how to get multiple tests to confirm.

 

Why are people so shocked that they could get Covid? Why do some people not want to get tested for fear of testing positive (pre or post cruise)?

 

We are still in a pandemic and the best way to get back to cruising is to make sure that Covid doesn't get on the ships. The best way to do that is to test everyone.

 

The antigen test isn't entirely reliable, so it's certainly not unreasonable to go for a second test if you test positive. And rather than automatically canceling their cruise at a positive antigen test, I can hardly blame people for wanting to test again to be sure.

 

If you have one positive antigen test and one negative antigen test, I believe you are likely negative because I think the false negative rate is much lower than the false positive rate. But personally if I had a positive antigen test I'd want to get a PCR test to know for sure.

[Prismism]

On 8/7/2021 at 9:30 AM, K_e_short said:

I have been reading most of the comments and questions regarding the changes Carnival made regarding pre cruise testing.

 

I keep reading so many people saying "false positives".

 

Has anyone thought that perhaps if they test positive they actually have Covid?

 

That is why testing is required before you cruise now. To prevent people who have Covid from getting on a cruise ship.

 

You can have Covid with no symptoms at all, children especially.

 

I completely agree the frustration on changes, added costs, stress, etc. I get it. My December cruise is up in the air until they make a decision about December.

 

Perhaps realizing that testing positive means you have Covid and getting on a cruise ship and infecting others (vaccinated or unvaccinated) is very selfish.

 

(Oh and I'm not interested in hearing the stats on false positives. Get a second test if you want. Just bringing up an important point).

 

Have you not heard of all the highly publicized inaccurate test results over the past year? Even Elon Musk tweeted this earlier this year-

 

"Something extremely bogus is going on. Was tested for covid four times today. Two tests came back negative, two came back positive. Same machine, same test, same nurse. Rapid antigen test from BD."

 

Others have reported taking two antigen tests on the same day and having mixed results. "No symptoms. Was tested for COVID. Same machine. Left nostril positive . Right nostril negative."

[dltvermont]

On 8/7/2021 at 10:41 AM, lookitsmikel said:

This is a pretty simple one.... If you are vaccinated make sure you go get tested 3 days prior if you are getting the antigen test, this is the one with the high false positive rate. If it is positive, get the PCR test to verify it (as many testing centers would do anyways). PCR tests can take a couple days, but they have a very low false positive rate. If both are positive, guess what...  You have COVID 😄

Actually you have it backwards. The Antigen has more false negatives.

 

"What about accuracy? False negative results tend to occur more often with antigen tests than with molecular tests. This is why antigen tests are not favored by the FDA as a single test for active infection. Because antigen testing is quicker, less expensive, and requires less complex technology to perform than molecular testing, some experts recommend repeated antigen testing as a reasonable strategy. As with the molecular test, the false positive rate of antigen testing should be close to zero."

[sanger727]

OP, I get what you are saying; in fact there was a post on Royal Caribbean that I read. A woman and her family got sick in the week leading up to the cruise. Then they took their pre-cruise covid test and were shocked that they actually had covid and couldn't cruise. I would have expected anyone who had cold like symptoms to get a covid test proactively so they didn't spread it to others, but apparently covid is still news to some people.

 

That being said, while I don't mind covid testing pre-trip (as in before I get on the first plane), I really don't want to covid test mid trip. I also really don't want to get covid before or during my trip. But a mid trip positive stirs up a whole load of ***** that I would prefer not to deal with. If I don't have symptoms I would prefer not to know. What I've read about breakthrough infections with delta is still that if you have symptoms, your viral load is high enough to spread it. If you don't have symptoms, it's probably not. 

[Buckeyefrank100]

On 8/7/2021 at 10:41 AM, lookitsmikel said:

This is a pretty simple one.... If you are vaccinated make sure you go get tested 3 days prior if you are getting the antigen test, this is the one with the high false positive rate. If it is positive, get the PCR test to verify it (as many testing centers would do anyways). PCR tests can take a couple days, but they have a very low false positive rate. If both are positive, guess what...  You have COVID 😄

You are correct that PCR tests mostly do not present false positives, but that is a recent development.  PCR tests are run through cycles where the specimen concentration doubles each run through.  Initially, each lab was doing a different number of cycles.  I've heard as many as 42 or 43 cycles.  Finally, the CDC said a positive test was at 28 cycles.  There have been a lot of people who tested positive via PCR test that were never exposed to enough to make them sick or contagious.  A cynical person might conclude that the CDC changed testing cycle requirements to reduce the number of positives so the vaccines might be shown to work better....  but that's a conspiracy theory.