How accurate are tests on day of expected af?

[Hzky3]

Hi how accurate are results on the day of you're supposed period? I am cycle day 27 and have had 25 to 28 day cycles for the last year or so. Have tested today after one morning coffee looks to be completely negative how accurate is this result perhaps I'm just going to be late have no pms or pg symptoms

Tests from the first day of your supposed period are usually pretty accurate, as in most tests will advertise they give you an accurate result from the first day of your missed period. I know I've always had very obvious positives by the time my period has been due or late by a day. That being said of course, you may just have a longer cycle this month, so don't rule it out and test again if you still haven't come on in a couple of days