Positive but expired?

So I have an infertility exam today at 2, I tested this morning (expected to get period tomorrow) in case we got lucky I could cancel my apt & avoid paying $250. They look positive to me, only thing is I realized they are expired. One is a year & the other 2! The one that’s a year old I’ve been also using the OPKs and they seem to work- I just noticed they were all expired after taking them this morning. I plan on going to the store to get a current one, but I probably won’t make it until right before my appointment. Think it’s safe to go ahead & cancel?