[Lewis Thomson (OP)]

Andy is looking for answers to this question.

"Given that a cold is a Coronavirus, can a Covid lateral flow test give a positive result for the common cold? What is the test looking for that is specific to Covid 19?"

Can you help him in the comments below....

[evan_au]

There are around 150-200 viruses that we classify as "the common cold". Only 4 of them are coronaviruses, so it's not really accurate to say "a cold is a Coronavirus".

You could produce a RAT test that detected one or a couple of the common cold viruses (eg adenoviruses), but it is unlikely that a single RAT test could detect all of them.

I am sure that one of the criteria for a successful COVID-19 RAT is that it did not react to the 4 "Common Cold" coronaviruses.

There are hints that people who have recently suffered from a "Common Cold" coronavirus are slightly protected from COVID-19, as their immune system responds to the family resemblance.
- This may be why children under 2 years old show some benefit from a COVID vaccine, while those 3-5 do not
- Children under 2 have lived during some form of lockdown, and may have had less exposure to the 4 "Common Cold" coronaviruses, and so may have less protection against COVID-19 than slightly older children.

https://en.wikipedia.org/wiki/Common_cold

[evan_au]

can a Covid lateral flow test give a positive result for the common cold?

This would be called a "False Positive": Indicating that you have COVID, when in fact you have something much milder.
- The antibodies used in these tests are quite specific, so provided you use an antibody target that is absent on the "Common Cold" coronaviruses, you should get a low False Positive level
- Providing that the test isn't too old, hasn't been exposed to high temperatures, etc

It is harder to control how well people do their swab, whether they do it 1, 3 or 5 days after they are infected, whether they have just drunk coffee, etc. So False Negatives are more of a problem: Indicating that you don't have COVID when in fact you do have it.

Lateral Flow Tests are generally considered to be 80% - 90% accurate, which is enough to indicate that you are infectious today. Taking one of these every 2 days gives a pretty good detection rate.
See: https://en.wikipedia.org/wiki/False_positives_and_false_negatives