In early pregnancy, doctors might use one of two types of blood tests to check a woman’s levels of hCG, a pregnancy hormone. The most common is a quantitative hCG blood test, which evaluates the level of hCG in the woman’s blood and returns a number, with the measurement unit being mIU/mL, or milli-international units (thousandths of international units) of hCG per milliliter of blood.
Quantitative hCG blood tests provide highly useful information about women having miscarriage symptoms in the first few weeks after conception. Comparing levels from two quantitative hCG blood tests to look at the hCG doubling time over two to three days can give a strong indication of whether or not the pregnancy is progressing as it should be at that point in time, helping a doctor make a proper assessment.
Doctors may also use qualitative hCG blood tests, which merely return a yes or no answer on whether or not the woman has hCG in her blood. Qualitative hCG blood tests are not as widely used in pregnancy now that highly sensitive urine-based pregnancy tests can provide the same information in a less invasive manner.
Sources:
American Pregnancy Association, "Human Chorionic Gonadotropin (hCG): The Pregnancy Hormone." July 2007. Accessed 17 Jan 2008.
