Is A Blood Test For Pregnancy More Accurate Than A Urine Test?
Blood Pregnancy Tests
A pregnancy blood test or a pregnancy serum test is a test that measures the exact amount of the pregnancy hormone, human chorionic gonadotropin (hCG), in the bloodstream of a woman to detect pregnancy. Human chorionic gonadotropin (hCG) is a hormone that is produced by the placenta of a pregnant woman. It is detectable in the blood and urine within 10 days of fertilization. There are two types of blood pregnancy tests, namely, quantitative blood test which measures the exact amount of hCG in the blood and qualitative hCG blood test which gives a simple yes or no answer to whether you are pregnant or not.
How early can blood test detect pregnancy?
Blood tests can detect a pregnancy earlier than a home pregnancy test. They can detect it about 7-12 days from possible conception and can also measure the concentration of human chorionic gonadotropin hormone in your blood. This can be very helpful information for your doctor in tracking certain problems in pregnancy. If you suspect any symptoms of pregnancy like delayed menstrual period, breast tenderness, pelvic pain, irregular spotting or vomiting. You must get a pregnancy blood test done to confirm or rule out pregnancy.
Is a blood test for pregnancy more accurate than a urine test?
The latest news does say that blood tests are indeed more accurate than home urine tests. Recently, research presented at the Scientific Assembly of the American College of Emergency Physicians revealed that almost six percent of negative urine pregnancy tests can be false negative, meaning the women is indeed pregnant despite a negative urine pregnancy test. Initially, the researchers had expected to find urine pregnancy tests as accurate as blood tests.
When researchers looked at 662 women at Henry Ford Hospital who received both urine and serum human chorionic gonadotropin (hCG) tests for pregnancy. Six women, out of the 102 negative results, tested negative with the urine pregnancy test, yet their blood pregnancy test indicated they were indeed pregnant. Five of these women with false negative tests had serum human chorionic gonadotropin (hCG) levels in the range 11 to 97 mU/ml, which is normal for the first month of pregnancy.
Though researchers caution that these false negative numbers may be higher than what is actually found in practice, Henry Ford Hospital now uses blood pregnancy tests as the standard for women less than four weeks past the date of their expected menstrual period. So we can conclude that blood tests for pregnancy are more accurate than urine pregnancy tests.
What do the pregnancy blood test results mean?
A healthy pregnancy is expected to show a normal pattern of HCG levels over time. In a pregnant woman the level of human chorionic gonadotropin (hCG) increases throughout the first trimester, then gradually decreases over time. In the first trimester, a woman may have this test done repeatedly to see if the level rises normally. If it doesn’t, the pregnancy is often considered in trouble. After childbirth, miscarriage, or abortion, the level should quickly decrease to zero.
How reliable are blood pregnancy tests?
Home pregnancy tests are around 97% accurate when done correctly. However, a blood test is more accurate, but not necessarily more sensitive. The results depend a lot on the lab, methodology and technique of the blood test performed.
A quantitative blood test, usually called a beta human chorionic gonadotropin (hCG) test, measures the exact units of hCG in the blood. That means it will detect even the most minimal level. There is another type of blood test sometimes called a qualitative human chorionic gonadotropin (hCG) test. This is a test that simply gives a yes or no answer to whether you are pregnant.