Blood tests for detection of a pregnancy are extremely effective and can be done a lot earlier as compared to urine tests. They have an accuracy level of 99% as compared to the 97% for home pregnancy urine tests. The main advantage is that clinical blood tests for pregnancy can be performed just 7 days after ovulation, which would be a week before your next period is due. A urine test on the other hand is ideally conducted after the first day of a missed period or about 2 weeks after conception.
Pregnancy tests, whether blood tests or urine tests use a common standard or marker for the detection of a pregnancy. If there is a pregnancy the placenta begins to release a hormone called human chorionic gonadotropin or hCG. This hormone is detectable in both the blood and urine of a pregnant woman within ten days of fertilization. Blood tests for a pregnancy are conducted at a clinic or your doctor's office and can detect a pregnancy by measuring the levels of hCG in the blood. Pregnancy blood tests could be of two types:
- There are quantitative blood tests that identify a pregnancy by measuring very precisely the amount of hCG present in the bloodstream, and this test can also reveal how far along the pregnancy has progressed.
- Qualitative blood tests on the other hand do not measure hCG levels, but it does detect a pregnancy through the detection of hCG in the blood.
Pregnancy blood tests are performed just like any other simple blood test at a lab or clinic. If conducted in a clinic, the blood sample is then sent to a laboratory for testing after which you could expect the results within a day or two.
Home pregnancy tests are not as accurate as blood tests possibly also because of improper handling and attention to the details. Even in a lab environment, the accuracy of tests does depend to some extent on the methodology of the lab and the technique of the blood test performed. Pregnancy blood tests however are useful not just for detection of a pregnancy but also for monitoring a pregnancy. This is because the levels of hCG in a pregnant woman increase through the first trimester, after which they gradually begin to decrease. The test can be repeated during the first trimester to detect if there is a normal rise in the levels.
Submitted by N on January 6, 2010 at 09:03