Human chorionic gonadotropin is a hormone that is manufactured by an embryo and then placenta during pregnancy. A quantitative hCG test is a blood test that determines the amount of the hormone in your body.
Minute levels of hCG exist in your bloodstream even when you're not pregnant. The levels, however, are generally too low to be detected on a urine pregnancy test. Megan Clarke's research on PeeOnAStick.com indicates that the most sensitive pregnancy tests can detect levels at a minimum of five milli-International Units per milliliter.
Effect of Menopause
HCG levels of post-menopausal women may be higher than those of women of childbearing age. According to the American Pregnancy Association, post-menopausal women may have quantitative hCG levels of up to 9.5 mIU/mL, whereas non-pregnant women of childbearing age may have levels less than five mIU/mL.
Effect of Pregnancy
Clinically, a quantitative hCG level greater than five is considered positive for pregnancy (post-menopausal women the exception), according to American Pregnancy.
Levels During Pregnancy
Dr. Marjorie Greenfield in her article on DrSpock.com states that hCG levels double approximately every 48 hours during early pregnancy. According to the American Pregnancy Association, normal quantitative hCG test levels can range between five and 426 mIU/mL at the time you miss your period, which is about 14 days after ovulation.
Unless miscarriage is suspected or if levels are being monitored after a pregnancy loss, you will probably not have more than one quantitative hCG test in early pregnancy.