Is it possible to have a positive home pregnancy test 5 days after unprotected sex?

Sure, but...: A woman can have a positive home pregnancy test 5 days before sex, 5 minutes after sex, or 5 days after sex... the positive result just shows she was already pregnant before this episode of sex. A urine pregnancy test gives a very reliable result 2-3 weeks after sex (2-3 weeks after when conception might have occurred), or 1 week after missing a period.

See below: Conception occurs within day or so of the sex. It takes about 3 weeks for the embryo to make enough HCG for a positive pregnancy test. Blood test may be done a day after a missed period. Home pregnancy tests should be done 4-5 days after the missed period. If the result is negative repeat the test in 4-5 days. Use first morning urine and follow instructions for the test carefully.