How long do you have to wait after conception to have an accurate pregnancy test?
Normally it is around 12 days past ovulation, some women can test accuratley at 9 days past ovulation. Take a sensitive test (the ones that say 5 days before your missed period) and if it is negative, take another one the day after your period is due if it doesn't come incase you implanted late.
Modern home pregnancy tests are pretty accurate and can detect the chemical markers for pregnancy about 6-12 days after conception. There are (more expensive, laboratory only) tests that are able to detect pregnancy as little as 48 hours after conception. If you're asking how long it takes to take the test ... not long at all, maybe 15 minutes.