less likely than a false negative?

Without more information I would start with either error is equally possible.

the antibody/antigen on the card has degraded and thus will not report a signal.

But a false positive means that *something* is binding to something. The most likely things binding are the original intended targets.

I really should have done a negative control. I will repeat the tests again later today and report back.

In a lack of signal. You could be right. I offhand don’t know why degradation could also not cause an increase in signals.

I guess I view the tests as having a certain amount ‘noise’ in their results even when new, and that noise results in both false positives and false negatives. As the tests degrade over time, the noise level increases, the errors increase, but that applies to all errors.

I took a Covid test and gave him my extra test. It was expired by about 9 months. My result was positive, his was negative.

Now I know that doesn't mean squat. It's not scientific. But either we both had Covid and one test worked and one didn't (same box) or we both didn't and one test worked and one didn't, or I had Covid and he didn't. There's no way to know!

But that's my experience, for what it's worth, which isn't much. I'm pretty sure I had Covid. It would be my second time.

Like you, I also tested positive recently using a test that expired last year. My son had already tested positive several days earlier, and I had started to develop symptoms too, so I was pretty sure the result was correct.

A false positive doesn't really make sense, scientifically. An expired test might be less sensitive, so it would be more likely to give you a false negative, but there's no reason it would detect virus particles that aren't there.

Plus, the fact that my test band was really solid and his was less so, and that he had symptoms about a week before me.

were extended by the FDA, suggesting the tests last longer than the original expiration date. Were these expired based on the printed date or based on the new dates: https://www.fda.gov/medical-devices/coronavirus-covid-19-and-medical-devices/home-otc-covid-19-diagnostic-tests

Thanks for confirming

Last edited Mon Oct 28, 2024, 06:17 AM - Edit history (1)

They're useful if the lab that made them is compliant with HHS-OIG. Here's a short description of how it should be done: https://www.jdsupra.com/legalnews/5-tips-for-lab-compliance-in-2022-9912720/