How long after sperm meets egg can you tell your pregnant by a test?

Conception occurs when the egg and sperm join, it can take 7 to 10 days past conception for the fertilized egg to travel from the fallopian tubes to the uterus where the embryo will implant into the lining. After implantation it may take three or four days for the body to produce detectable levels of hCG. Every woman and every pregnancy are different, but 10 to 14 days after conception most women will have a positive pregnancy test.