If conception possibly took place a week prior to your period and currently about 4 days late when would be the bet time to take a test?

Wait one more week: A urine pregnancy test done correctly gives a reliable result 3 weeks after sex (3 weeks after when conception might have happened) or 1 week after missing a period. If done sooner, a positive result is likely real, but a negative result may be due to testing too soon, and therefore lead to a repeat test. If a woman has her normal regular period, then she is not pregnant, and a test is not needed.