how accurate is the pregnancy blood test
1 Be sure to follow the instructions exactly for accurate results.  Human chorionic gonadotropin (hCG) can be found in the blood before it can be found in the urine. A blood test can confirm a pregnancy about 6 days after the fertilized egg implants into the uterus (even before a missed menstrual period). To learn more, see the topic Human Chorionic Gonadotropin (hCG).