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Scientists urge caution on use of lateral flow tests to screen for Covid-19
useful info here for anyone picking up students from Uni returning home for Christmas who are taking LFD tests -- lateral flow tests.
use only as a guide. a sensible approach from my brother in Law who has both sets of elderly parents coming for Xmas is that both sets need to properly isolate for a week before coming, thus protecting all and reducing risk.
Similarly a student returning home, even with a negative test should remain 'distant' for the first week.

"Jon Deeks, a professor of biostatistics at the University of Birmingham, said that the test is ‘entirely unsuitable’ for community testing, such as that planned for university students in the run-up to Christmas. ‘As the test may miss up to half of cases, a negative test result indicates a reduced risk of Covid, but does not exclude Covid,’ Deeks added. ‘This evidence raises serious concerns that the benefits are likely to be few, with serious risk of harm if the public are misled by unjustified government claims of this test’s high performance.’
 Deeks pointed out that the report’s headline figure of 76.8% sensitivity mixes data from different settings. One study of Innova’s device at a testing centre found that the device appeared to miss one out of every two Covid-19 cases (58%). Another study using nurses to test patients suggests it missed one out of every four cases (73%)."

there are more enthusiastic articles and research which i shall add below, but it would seem these tests are a 'guide' and should not be considered definitive -- as with so much Covid info!!

https://www.chemistryworld.com/news/scientists-urge-caution-on-use-of-lateral-flow-tests-to-screen-for-covid-19/4012763.article


this is one of the source papers https://www.bmj.com/content/371/bmj.m4262

and this is a readable extracthttps://www.ox.ac.uk/news/2020-11-11-oxford-university-and-phe-confirm-lateral-flow-tests-show-high-specificity-and-are#

this is the more negative evaluation https://www.bmj.com/content/371/bmj.m4323

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a

a Biostatician posted the above on Twitter today (taken from https://www.gov.uk/government/publications/community-testing-explainer/community-testing-a-guide-for-local-delivery#what-the-community-testing-programme-is ) saying

Mass testing in Liverpool MISSED ~50% of infections and ~30% with high viral loads.  Results are in this Government document, but no actual numbers or details are given. Absolutely URGENT that @DHSCgovuk  reports full data today and HALTS IMPLEMENTATION

i replied that

thx 4 posting LFD are indeed just a guide, son has just had one b4 leaving Uni- we must still maintain distance forweek really re symptom testing best is the very diagnosis of symptoms which points more accurately to C19 than any test & requires case to isolate 10 days from onset