A blood pregnancy test is done to determine if Human Chorionic Gonadotropin (hCG), which is a pregnancy hormone, is present in the blood. You can find out more about this if you are thinking of taking a blood pregnancy test.
First, you should know that the urine test (home pregnancy test), and the blood pregnancy test, which is also known as serum test, can both help to confirm pregnancy.
In most cases, most women are required to do a blood pregnancy test if they have done IVF and have been trying to conceive for a while.
If the blood test detects hCG in your blood, this will determine whether or not you are pregnant. When a sperm fertilizes an egg inside the fallopian tube, it will move downward and get implanted inside the uterus, in nine days after fertilization.
As soon as the implantation takes place, the developing placenta will start to release hCG into the bloodstream. The hormone can then be detected in the blood even before you have the first miss period, as early as 6 days after the implantation .
Taking a Blood Pregnancy Test
When you are ready to take a blood pregnancy test, you will have two different types to choose from. There is the quantitative blood pregnancy test that will measure the exact amount of Human Chorionic Gonadotropin in the blood, and the qualitative blood pregnancy test that will confirm if the hormone is present.
If the test shows the hCG level below 5 ml/mIU, it will be a negative one. If the hCG level is in the range of 5 to 25 ml/mIU, this result will be equivocal, and one more test has to be done in a few days to confirm the pregnancy.
The quantitative blood pregnancy test is said to be the most accurate because it will tell the exact hCG level. This result will help your doctor to give a clear determination as to whether or not a normal pregnancy occured or if you have to do another test.
The two types of blood test can give a false negative result. This happens when the test cannot detect the existing hCG level. As an example, the test result can be a negative one if its set to pick up 25mIU of hCG and your existing level comes back as 20 mIU, although you are pregnant.
You are recommended to take the test after a few days if a qualitative or Home pregnancy test (HPT) gives a negative result and you are still seeing signs of pregnancy.
When to Take the Test
The hCG levels will increase steadily during the first 10 weeks of pregnancy, doubling within the first 4 to 6 weeks about every two days. It is during this time that women usually believe that they are pregnant and might start to see some early signs.
You can confirm pregnancy as early as 7-10 days after conception by blood hCG test whereas it is usually advised to take a urine pregnancy test on the first day of your missed period, 2 weeks after conception.
You could repeat the testing after a few days to do a comparison of the hCG levels. As expected in normal pregnancies, the level of hCG should indicate an increase and upward pattern. In the event that the hCG levels are not following the normal upward pattern, it might be a sign of an abnormal pregnancy, ectopic pregnancy, and an impending miscarriage.
However, the levels of hCG will be just one clue as more tests would have to be done to confirm abnormalities. Your doctor could do a thorough physical examination, have a discussion, and perform other tests to get a definitive diagnosis.
Blood Pregnancy Test Results
If you do this test too early, you can get a false negative result even though you’re pregnant as there might not be sufficient hCG in your blood. The test result can be positive if you are not pregnant because you might be using medications containing hCG. This is why it is important to let your doctor know about any medication that you are using before doing the test.
The blood pregnancy tests which are done at a doctor’s office often have an accuracy rate between 98 and 99 percent. The tests can be done seven days after your ovulating period and still give accurate results.
Another thing that you should know about blood pregnancy tests is that it could take you longer to get the results when compared to urine tests. This time varies as it will depend on the lab that is used and it could range from one hour to several days.
Lastly, you have to visit a medical office when taking a blood pregnancy test which makes it more costly than a home pregnancy test. You also have to take time from your schedule to do this test.