If you suspect that you are pregnant, your physician may order a blood test to confirm it. First, it is important to know that pregnancy tests, both blood tests and urine tests, work the same way. They measure the presence of human chorionic gonadotropin, or, simply, hCG. hCG is the pregnancy hormone, which is made when the fertilized egg implants into the uterus. Detecting this one hormone is significant, as hCG is only present when a woman is, or has recently been, pregnant.
Qualitative Blood Tests
A qualitative blood test is a test that detects the presence of hCG, states MedlinePlus. If hCG is present in the mother's bloodstream, the test is positive, indicating that the woman is pregnant. Just like the urine tests that are available in the drug store or your doctor's office, a qualitative test is only able to tell you if hCG is present in your system. Your lab report will indicate only a positive or negative result.
Quantitative Blood Tests
A quantitative blood test, also known as a beta hCG, measures the exact amount of hCG present in your blood, explains Women's Health. Its accuracy is due to the fact that it can detect trace amounts of hCG. As your pregnancy progresses, your levels of hCG will increase and decrease at a predictable rate. A series of quantitative results is an indicator of how your pregnancy is developing.
Why Have a Blood Test?
Blood tests can detect trace amounts of hCG earlier than home pregnancy tests or, even, urine tests performed at your doctor's office. A blood test can be performed six to eight days after ovulation. If you have undergone fertility treatments or have certain medical conditions, knowing you are pregnant days earlier can ease the anxiety commonly experienced in the two-week wait between ovulation and your expected period.
