If you was to have an ectopic pregnancy, it would be from shortly after conception, ectopic pregnancy means the blastocyst has implanted outside the uterus (normally in the tubes), so when your due...
The most accurate tests claim to have around an 80% accuracy rate five days before your missed period. The day you are supposed to have your period the accuracy goes up and it goes up even further...
you can take the test 5 days before your period is due and if it is positive then you need to see your doctor to determine how far along you are. but they go by the 1st day of your last period so...