Will a covid test be accurate even after symptoms have ended?

[Laanet]

Does anyone know how accurate a covid test is likely to be if you do it after symptoms have gone?

My son developed a cough on Saturday and was coughing quite a bit Saturday evening/night and on and off during the day Sunday but by the time we got the home test through and managed to adminster it (this morning, Monday) his cough had pretty much gone. So I'm wondering if he has therefore 'recovered' from whatever virus he had (whether covid or not) and therefore it might not show up in the test even if it was corona? It's still only 2 days since onset of symptoms but since there aren't any symptoms left I wasn't sure...

I tried googling but haven't been able to find anything useful!

90 days is the guidelines for a covid test to remain positive after symptoms start

90 days??

That’s my understanding too @Livedandlearned. I think it can take a long time for your body to clear it enough to not test positive but apparently you’re not infectious that whole time.

It's definitely true that you're not infectious, I think that only lasts for about a week.

We have lateral flow tests given to us at work and it says in the instructions not to use for 90 days after testing positive as the results won't be reliable.

A test should be done within 5 days of symptoms in Scotland and within 8 in England I think.

If you have tested positive you shouldn't have a retest for 90 days if you have not had symptoms again as residual virus could cause you to test positive even if not contagious

Thanks all. I guess if it might show up to 90 days later then I shouldn't be worrying too much about it not showing up on day 3!

It might give a positive test up to 90 days but you wouldn't be able to have a test if its more than 5 days from symptoms (scotland) or 8 days (england). Not everyone still tests positive for that amount of time