Originally Posted by
greg5
Seems like a good thread to continue this discussion:
I've got an upcoming ZRH-LHR-SEA. From what I understand, I can do my test here in ZRH the day before the ZRH-LHR, and as long as my layover isn't more than 24 hours I'm good with the test done in ZRH. I've got a layover of just under 22 hours.
Am I correct?
Yes you are correct, but with so much time in LHR I would personally do the test in the UK, not least to minimise the risk of arriving positive in the USA.