Real Word Performance of Lateral Flow Tests (aka rapid antigen)

31 Dec

Rapid antigen tests, although cheap and fast, have escaped much critical review until now. In the real world, antigen’s claim of 80% sensitivity is not what the experts see and at best, antigen tests are only 50% accurate. Why hasn’t every media outlet in the world covered this?

Not all antigen tests are created equally.

Sensitivity varies wildly among antigen brands from 38.32-99.19% sensitivity. The WHO recommends antigen tests should have a minimum of 80% sensitivity and 97% specificity yet we know that many are not even close. Why are they still being sold?

“Sensitivity of antigen tests varies wildly among brands from 38.32%-99.19% sensitivity, according to a study of 26,000 test results.
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— BMC Infectious Diseases

The US FDA is leading the way and holding antigen test providers accountable. As of 28 May 2021, the FDA ordered a recall of Lepu Medical Technology antigen tests. 10 June 2021, the FDA recommended that all Innova antigen tests be destroyed and issued a Class 1 recall (the most serious type of recall). Remember that Innova supplied all lateral flow tests to the UK NHS for more than a year, even after the FDA recalled them. Ellume was recalled on 16 November 2021. On 28 January 2022, the FDA issued a warning that Empowered Diagnostics CovClear antigen tests cannot be sold or used in the United States because of the “higher risk of false results” another Class 1 recall. There are many more just like these.

EARLY DETECTION STOPS THE SPREAD; LATE DETECTION INCREASES THE SPREAD.

One of the biggest risks with antigen tests is they do not detect COVID in the early infectious stage. That can mean up to four days of someone unknowingly contagious, living their normal life and spreading the virus to everyone in close contact. Even if you test everyday, lateral flow will not detect COVID until you have a high viral load. According to the American Society for Microbiology “When used at home by the general public, rapid-COVID-19 antigen tests perform at the very bottom of the COVID-19 testing cascade.”