How correct is home pregnancy test? is it really advisable to take after 2 weeks of intercourse and not less than 1 week?

An excellent test: 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.