Rapid Antigen Detection Tests

S

Sophrosyne

Registered User
Messages
1,538
Interim Report of the Rapid Testing Expert Advisory Group

The Expert Advisory Group on Rapid Testing (RTEAG) was appointed by the Health Minister in July 2021.

Its remit is to provide support and guidance to Government departments seeking to deploy Rapid Antigen Detection Tests (RADTs) in the sectors they support.

Terms of reference:

  • Communication with government departments on their requirements for RADTs in the sectors they support
  • Development of tools for operational readiness to support use of RADTs as required and to support and inform the education, information and communication resources that sectors will develop themselves
  • Rapid and real-time synthesis of the scientific evidence to guide the appropriate use of tests in areas that are important to the safe and sustainable reopening of our society.
The link to the report appears at the end of the above linked page.
 
According to the HSE chief, Paul Reid, in today's Irish Times, about 1,000 antigen tests a day have been sent out to asymptomatic close contacts of Covid cases.
 
Strange results from positive antigen tests with followup negative pcrs:


In the first month, 31,850 antigen test results were reported by close contacts - 21,579 “not detected” or negative results, and 10,271 “detected” or positive, according to data presented at a National Public Health Emergency Team (Nphet) meeting this month. Just 5,741, or 54 per cent, of these positive antigen test results were confirmed positive with subsequent PCR testing.

www.irishtimes.com

Barely half of positive antigen test results confirmed by PCR testing

Average of almost 4,000 antigen tests carried out on close contacts since end of October
www.irishtimes.com www.irishtimes.com
 
odyssey06 said:
Strange results from positive antigen tests with followup negative pcrs:
Click to expand...
I was surprised by that too. When you add in the up to 50% false negatives into the mix, I think we did well not to depend on them too heavily.
 
I'm wondering are people scamming the system, is it just people's word that they tested themselves and got a positive result that then subsequently tested negative on professional pcr test. Maybe people are using this to get time off work. No wonder Tony holohan doesn't trust self administered antigen tests.
How can a test manufactured to laboratory standards throw up so many false positives, if that was true it would be picked up in Germany or uk where they have been using them for ages
 
joe sod said:
I'm wondering are people scamming the system, is it just people's word that they tested themselves and got a positive result that then subsequently tested negative on professional pcr test.
Click to expand...
I don't see what the goal of such a scam would be when they know the PCR test will be negative.

joe sod said:
if that was true it would be picked up in Germany or uk where they have been using them for ages
Click to expand...
After the Irish report I did a little searching and turns out high false positive rates have been reported elsewhere and for more than a year at this stage. Here's a study from earlier this year on the burden caused by similar rates of false positives in Germany.
 
Bought the antigen tests today. The leaflet says they have a 99% sensitivity and a 98% specificity. In common language that means 1% false negatives and 2% false positives or maybe the other way round. Sounds good enough for me.
Of course self assessment cannot be relied upon for official purposes. Would you trust a pilot if you only have her word that she has 20/20 vision?
 
Last edited:
Duke of Marmalade said:
Bought the antigen tests today. The leaflet says they have a 99% sensitivity and a 98% specificity.
Click to expand...
Minimum standards allow for tests with 80% sensitivity, but in reality most places are seeing false positive rates far in excess of that tolerance. The specificity assumes an ideal sample, and accuracy is significantly affected by the user, with untrained testers in study last year returning a ~50% false negative rate.
 
Leo said:
Minimum standards allow for tests with 80% sensitivity, but in reality most places are seeing false positive rates far in excess of that tolerance. The specificity assumes an ideal sample, and accuracy is significantly affected by the user, with untrained testers in study last year returning a ~50% false negative rate.
Click to expand...
Have you got those the wrong way round? The way I try and work out which is which is ask what does 100% sensitive mean? It means you never get a false negative. Similarly 100% specific means nothing else can give a positive result i.e. no false positives.
But I note your figures which definitely conflict with the figures on the leaflet.
 
Failed a Lidl test on Christmas day after eating too much for the dinner.
Did 2 follow up tests with kits from different manufacturers and both were negative. The 2nd and 3rd tests were obtained from a visiting emigrant curtesy of the NHS.
I suspect eating too much for the dinner was the cause of the positive test.
 
Duke of Marmalade said:
The way I try and work out which is which is ask what does 100% sensitive mean? It means you never get a false negative.
Click to expand...
Yeah, it means you never get a false negative provided with a perfect sample. In the real world it seems many people fail to take an effective sample.
 
RichInSpirit said:
Failed a Lidl test on Christmas day after eating too much for the dinner.
Did 2 follow up tests with kits from different manufacturers and both were negative. The 2nd and 3rd tests were obtained from a visiting emigrant curtesy of the NHS.
I suspect eating too much for the dinner was the cause of the positive test.
Click to expand...
On social media there are a lot of reports of false positives with Genrui brand which i think is sold in LIDL.
 
Last edited:
The Health Products Regulatory Authority (HPRA) today states that based on its advice, retailers are removing the Genrui SARS-CoV-2 Rapid Antigen Self-Test from sale on a voluntary basis pending further investigation. This follows receipt by the HPRA of over 550 reports in recent days from Irish consumers of false positive results associated with the use of this particular antigen self-test.

Update: HPRA issues safety notice confirming recall of two batches of Genrui SARS-CoV-2 Antigen Self-Test

The objective of the Health Products Regulatory Authority is to ensure in so far as possible, consistent with current medical and scientific knowledge, the quality, safety and efficacy of medicines available in Ireland and to participate in systems designed to do that throughout the European Union.
www.hpra.ie www.hpra.ie
 
Am reading in New Scientist that for Omicron it is important to swab for saliva/back of throat as the variant appears to reach high levels in saliva.
 
You must log in or register to reply here.
Back
Top