I have taken enough pregnancy tests (only a few) before AF is due. They have always turned out to be a BFN. So I try not to test until at least a day after my AF. I can see that if I try to test before AF is due and then its a negative and then AF is late then it costs me twice as much. I'm a cheap skate... Last time I tested in 2009, it was two days after my missed AF, w/a BFN. AF didn't come still, I didn't retest, instead I waited for a week after AF missed and made a Dr. appointment which was 3 days later. Blood test came up BFN also. 2 days later I got AF. I guess I could have tested again on my own rather than go to Doc but in the end I still came out better copay wise to go for the blood test. Luckily, AF came pretty soon after testing because I can't imagine having to go back again.