How long after sex can I take accurate pregnancy test

Four weeks... no sooner.

After 19 days..!

after 19 days...!!

Where did you get that number from? Because you won't get an accurate test result you can rely on until you are at least 14 days LATE for your period... you could be as far along as 6 weeks at that point... not 19 days... at 19 days you will usually get a negative.