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Hi Glenda,
I hope you’re doing well.
The reporting of sensitivities/specificities for the RATs varies
significantly depending on the source and the test brand. Studies have
shown that RATs, in general, are more accurate in symptomatic vs
asymptomatic people. And the positive predictive value varies depending on
prevalence of COVID-19. So places with relatively low prevalence (like
Australia) will naturally have more false positives. Something to keep in
mind as home tests are rolled out soon.
I’ve been pulling together a position paper on RATs for Uni Melb thus the
reason I’ve been doing alot of reading about the tests. Here are a few
resources you may find useful:
https://www.thelancet.com/journals/eclinm/article/PIIS2589-5370(21)00234-0/fulltext
Overview:
https://www.cochrane.org/CD013705/INFECTN_how-accurate-are-rapid-tests-diagnosing-covid-19
and
full article:
https://www.cochranelibrary.com/cdsr/doi/10.1002/14651858.CD013705.pub2/full
Cheers
Crystal
*Crystal Polson, MSN, RN, NP, PGCertIPC* | Infection Control Coordinator
Public Health Network
*M*: 0434 831 715 *E: *crystal.polson@unimelb.edu.au
On Thu, Oct 28, 2021 at 6:08 PM SmartDentist
wrote:
> Hi Leanne and Crystal,
> I could only find 2 articles with the stats for false positives with RAT
> in general and the articles said 6% and 8% which seems overly high.
> This isn’t in regard to people recovering from Covid but I also wonder as
> we have move into RAT for asymptomatic people in our workplace as a
> precaution, how high will false positives actually are in general.
>
> Interested also in any other information on false positives.
>
> kind regards
> Glenda Farmer
> Infection control and prevention
> Smartdentist.com.au
> smarthealthcare.com.au
>
> On 28 Oct 2021, at 12:46 pm, Crystal Polson wrote:
>
> Hi Leanne,
>
> I hope you’re doing well.
>
> People who have tested positive for SARS-CoV-2 can have detectable virus
> in upper respiratory secretions for up to 3 months. However, the virus is
> no longer replicating – and it is highly unlikely individuals are
> infectious – after around 10 (mild-moderate illness) to 20 days (severe
> illness) after developing symptoms.
>
> So people who have recently recovered from COVID-19 may test positive on
> the RAT and the result may be a true positive depending on the timeframe.
> But this doesn’t mean they are infectious (same as with PCR test).
>
> If a person who had COVID develops symptoms again, and it has been three
> months since their first infection, they should get a PCR test as it is
> possible to become reinfected with SARS-CoV-2.
>
> NSW Health recommends against asymptomatic testing (such as surveillance
> testing) for 6 months after a person has recovered from COVID due to the
> possibility of a positive result (again, could be true positive but person
> not infectious). I can’t find a similar recommendation for Victoria but I
> think this is a good guideline to use.
>
>
> Cheers
> Crystal
>
> *Crystal Polson, MSN, RN, NP, GCert IPC* | Infection Control Coordinator
> University of Melbourne | Public Health Network
> *M*: 0434 831 715 *E: *crystal.polson@unimelb.edu.au
>
>
> Please note, I do not work on Fridays
>
>
>
>
>
>
>
>
>
> On Thu, Oct 28, 2021 at 10:40 AM Leanne IAnson Leanne.IAnson@tlchealthcare.com.au> wrote:
>
>> Hi All,
>>
>>
>>
>> Just wondering if anyone has heard data regarding false positive RAT in
>> those that have had covid-19.
>>
>>
>>
>> We have been informed it is pointless to use RAT on those that have had
>> the virus as they often show false positive results ,
>>
>> Appreciate all feedback
>>
>>
>>
>> Kind Regards
>>
>>
>>
>> Leanne IAnson
>>
>> Infection Prevention and Control Manager
>>
>>
>>
>> *TLC Healthcare*
>>
>> Mobile:0487210205
>>
>> [image:
>> https://www.tlchealthcare.com.au/assets/email/tlc-healthcare-combined-2018.jpg%5D
>>
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