A qualitative or quantitative blood test measures the level of human chorionic gonadotropin (hCG) hormone in the blood serum. This hormone is secreted by the placenta after the fertilized egg implants in the uterine wall. The qualitative test detects the presence or absence of the hormone (positive/negative), while the quantitative test precisely measures its concentration in milli-international units/mL. It is considered more accurate than a home urine test.