BW, I had a level of 0 in all 7 cycles, so I would think a HCG level would indicate implantation, however brief. As far as I'm aware, hcg is only produced upon implantation, but anything below a level of 5 is considered a -ve.

I was told that implantation occurs fairly often, but many are lost even in women with no fertility issues. I never achieved implantation in all previous 7 cycles, but that is incredibly uncommon apparently. Given that my fertility issue was blocked tubes, I should have achieved implantation at least some of the time, even if it didn't result in a pg.