Full report is available as a pre-print led by @siantphillips2
Information given by websites selling home self-sampling COVID-19 tests: An analysis of accuracy and completeness medrxiv.org/content/10.110…
2/11
A simple search of UK and US websites (end of May) found 27 websites selling 41 tests direct to user home self-sampling and testing for COVID-19. Seems a particular UK problem as 39 tests were for sale in UK and only 2 in US.
3/11
Many websites DID NOT provide
the name or manufacturer of the test (32/41; 78%),
when to use the test (10/41; 24%),
test accuracy (12/41; 29%),
how to interpret results (21/41; 51%).
4/11
Sensitivity and specificity were the most commonly reported test accuracy measures
either were reported for 27/41 (66%) tests;
We tried to link these to evidence - but could only link these figures to manufacturers documents or publications for four (10%) tests.
5/11
Predictive values were not reported but indirectly implied
for 5 tests wesbites said “if it shows a positive result, it can only be for COVID-19” implying PPV=100%
four tests stated that tests sometimes show a negative result even if you are infected implying NPV<100%
6/11
For molecular virus tests,
only 9/23 (39%) websites explained that test positives should self-isolate,
and 8/23 (35%) explained that test negatives may still have the disease.
7/11
For antibody tests,
12/18 (67%) websites explained that testing positive does not necessarily infer immunity from future infection.
8/11
Seven (39%) websites selling antibody tests claimed the test had a CE mark, when they were for a different intended use (venous blood rather than finger-prick samples).
9/11
After MHRA stopped use of finger-prick samples
2 websites still selling
4 providing venous blood sampling
2 sent kits for purchaser to find own phlebotomist
6 stated out of stock / unavailable,
4 reported MHRA guidance and indicated that they had suspended sales.
10/11
Conclusions:
Web sales of home self-sampling COVID-19 tests
provide incomplete and in some cases misleading information about:
test accuracy,
intended use
and
test interpretation.
We MUST DO BETTER. Can the regulators read our paper and help? @MHRAgovuk
11/11
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Daily Testing in school study report is out but presentation by BBC here is SPIN SPIN SPIN
The trial failed to show convincing reductions in school absence, and could not rule out large increases in Covid transmission. Sensitivity of the test was 53%.
BBC says that reduced absence by 33%, but the ITT analysis in the text says 20% reduction with 95% confidence interval from 46% reduction to a 19% increases (p=0.27). So no convincing evidence of a reduction.
Participants were first tested with LFTs – 810 positive and 1736 negative. The investigators choose to test 217 of the 1736 negatives with PCR – that’s 1 in 8. This wasn’t a random sample as they were influenced by clinical characteristics as well as the test result.
2/9
The sensitivity / specificity calculation is based on all LFT+ves and 12.5% of LFT-ves as follows:
Results from the LIVERPOOL EVENT PILOTS have been published on line and in the media. Somehow I missed these coming out. cultureliverpool.co.uk/event-research…
No official report from @dhscgov as per normal.
Seems important evidence is being delayed once again.
1/7
The bottom line is that the events were safe.
Kudos to Liverpool PH Team.
But detail is interesting to see why they were safe.
2/7
First the infection rate in Liverpool was very low when the events were held
Negative LFTs required for entry. 5/13263 positive and excluded. Same-day PCR found 4 people positive who had attended with false negative LFTs. So 5/9 were picked up by LFT – 44% missed.
3/7
What do we known about ORIENT GENE used in the Daily Contact Testing Trial by the @educationgovuk and @DHSCgovuk?
There have been claims that this test is as good as others and has been reviewed by @MHRAgovuk for use in assisted testing. This is not right
1/10
The process does not make sense.
The MHRA never review products for assisted testing as they are professional use tests, which go through the self-certification process to get a CE-IVD mark.
MHRA doesn't go near this process.
2/n
In fact ORIENT GENE is not even on the MHRA register of products which is a requirement. You can check here - both for the product and manufacturer (sorry for the messy link).