I know that implantation bleeding is not as common as one might think... but...
I would like to know if a blood pregnancy test would be positive during or after implantation bleeding?

First, please read this info regarding implantation bleeding (https://www.askmehelpdesk.com/nursing/implantation-bleeding-31454.html).

Second, since it has not been proven, a pregnancy test is most effective after a missed period.