2 postives then 2 negatives 24hrs later

[candycrush789]

My ds (4) has had a snotty nose and I know covid is rife at the moment so tested him 3 days ago, negative. Tested him last night, and as I thought, positive. He's had a snotty nose and a bit of a cough so I wasn't surprised, tested again this morning and again positive. I tested again about an hour ago as we need to go to an appointment on Monday and his surgeon wanted to be updated with live results on facetime. Done one, and negative, completely stark white. Done another one as I thought it could be a dud, and no stark white again not even a hint of a shadow! What even is this was this 'fake covid' has anyone had experiences of this before? Obviously I'm overjoyed but I don't want to send him back to school and to his appointment if he's infected with covid! Nobody else has symptoms just him, and he's acting his normal self albeit a bit of a snotty nose and a cough!

The most likely is that either this is a false negative or he's thrown the illness off enough to not get a positive result now.

Test again on Sunday.

@MargaretThursday it was 2 different boxes that the negative tests come from, I did think this but surely 2 false negatives? 🤦‍♀️ I don't think the lfts are as good as they used to be!

You are in FaceTime to his surgeon on a Friday evening?

In any case stop testing him, if he needs a negative test to go for his appointment surely you only need to test that morning?

Yes, she's been working with my son since he was 3 months old. That's what I thought, but she wants live updates 🤷‍♀️🤷‍♀️

False negatives when someone has covid are quite high. Let's say it's about 25%, ie 1 in 4. I think it's more common than that, more like 40% but that also includes people doing the test badly, which, as you've got positives we can probably eliminate that.
If it's about 1 in 4 where you get a false negative for one test.
It's about 1 in 16 getting a false negative for two tests (1/4 x 1/4), which means for every 16 people with covid doing two tests, one of those people would get two false negatives.

False positives are much more rare-fewer than 0.5% or 1 in 200. We'll call it 0.5% though for simplicity.
To get two false positives you are looking at 1 in 40,000 (1/200 x 1/200). So for every 40,000 people without covid doing two tests, one of those people would get two false positives.

Hence me saying two false negatives are much more likely than two false positive.

It isn't quite a simple as that because the reason why you got a false positive on the first test might be the same reason you got a false positive on the second, and equally well the reason you got a false negative on the first might well be the same reason you got a false negative on the second.

I suspect the most likely reason for 2 positives followed by 2 negatives is that his viral load (and hence infectiousness) has reduced enough that he no longer is testing positive.

Which was why I suggested you tested again today or tomorrow before his appointment or going back to school. If he gets more negatives then I'd think he probably is clear enough. But if he gets another positive then assume he's still positive. That's what I would do.

I'm 90% sure DS gave me my last bout of Covid as he had the exact same symptoms, but he never tested positive.

Well I've just tested him again and negative 🤷🏻‍♀️🤷🏻‍♀️ so I'm guessing he's in the clear. Maybe if I tested him before I did he would of been positive for longer but he had no symptoms so had no reason to 🤷🏻‍♀️ how strange!

Of course it wasn't fake Covid. My DS was positive for one day - had symptoms a few days before while negative, positive for one then negative again.

LFTs show if you're infectious, it appears he's had it, recovered and he's in the clear now.

@CrocodilesCry when he had it before he had no symptoms but was positive for 5 days. This time he's still sneezing and has a cold but now testing negative 🤷🏻‍♀️🤷🏻‍♀️