period/r implant bleeding

Then if you have implantation bleeding, (16th-18 august) then would you already have hgc enough to show pregnant? in bloodtest on the 21st? because i had bleeding 3 days before test, and im not sure weather would show positive just after 3days???

and i have had no other bleeding or signs of periods, but don't understand if after implant bleeding do you still have enough HCG TO SHOW POSITIVE IN TEST???  


  i HAD EGG TRANSFER ON THE 10TH AUGUST MY EGG WAS ALREADY BLASTOCYST DAY FIVE, thats why i am so confused i didnt have to wait for it to fertilize just implant, if 6-12 days after ovulation (on the 4th august) so if egg implants you get bleeding (implant) how do i work out best time to test?