One of my faithful readers.. The definition of Beta Quant...
This is a test to quanitify the level of HCG or Human Choriogonadotropin, in a pregnant womans blood. HCG is the same thing that home pregnancy test pick up. The level in the blood starts out small, and doubles every day or so until the end of the first trimester. Then the levels start to drop.
Why test? A good implantation, is often proven by the doubling, or tripling of this hormone :) If you numbers were not rising, or were flat over a period of days, it is a sign of problems with the pregnancy.
Usually only women with infertility problems requiring medical assistance for pregnancy or women with a history of miscarriage have to under go this particular test.
Hope that answered your question ;)