Is it absolutely impossible for a pregnancy test to be positive one day after intercourse?

Can be positive if..: A pregnancy test can be positive one day after intercourse only if a woman was ALREADY pregnant from about a week or more earlier, or if the test has a false-positive result. (A false-positive result means the test shows a positive line, but the woman is not pregnant. A false-negative result means the test result is negative, but the woman is actually pregnant.)