November 29, 2011

First Response Pregnancy Test – Accurately Know Whether You are Pregnant

pregnancy testAny pregnancy test is formulated to diagnose whether a woman is pregnant or not. Most of the pregnancy tests including first response pregnancy test uses beta compartment of Human Chorionic Gonadotropin (hCG) – a hormone specifically increased when a woman is pregnant. hCG is released by placents, after the fertilized ovum is implanted in the uterus. It is a qualitative test, only to measure the presence of the hormone. The concentration where the result will be positive depends upon the brand. Many first response pregnancy test kit can detect as low as 1 mIU/ml of urine, others will be positive with 20 mIU/ml to 100 mIU/ml.

The next question that can come to our mind is that how you can check your pregnancy. Well, as it was said earlier, the first response pregnancy test measures the presence of hCG in urine. All these tests are card based tests and you have to put required amount of urine in the right slot. There is a test area and if you are pregnant, there will be two vertical bands over the test area. If your urine does not contain hCG, there will be only one band. Mid stream urine sample has to be used. To get this, you have to discard the first flow of urine, and then collect the middle part of urine flow in a clean glass pot and let the last part of urine flow again. First morning sample of urine is ideal as the hCG concentration is maximum in this time.

The accuracy of first response pregnancy test depends upon the time when you are performing the test. Most of the test kits available in the market can detect your hCG when you first miss your period. Almost 90% test results are positive at this period. The maximum positivity (almost 97%) can be achieved when you do the test seven days after you miss your period. Some modern kit can detect the hCG even 4 days before you expect your menstruation. If you assume that you can be pregnant, you can do this test.

Pregnancy Test

pregnancy testPregnancy tests are formulated to confirm that whether a lady is pregnant or otherwise. Tests for pregnancy have been in practice since early human civilizations. Previously pregnancy tests were mostly depending upon the different signs of pregnancy. But the modern pregnancy tests are based upon different chemical markers that start rising up when a lady is pregnant. These pregnancy markers can be found both in blood and urine. But due to patient’s convenience, modern pregnancy kit tests use urine as a sample.

The most common sought after chemical marker in pregnancy is Human Chorionic Gonadotropin. It is secreted by the HCG producing cells present in the placental wall. Although detecting HCG in urine is a confirmatory test for pregnancy, the level of HCG can raise in some rare tumors of the ovary, chronic diseases of liver, cancer of the liver and in some other disease conditions. In a pregnant woman, the level of HCG initially rises slowly and the pregnancy tests will give positive results only after 6 days of conception. Otherwise there is a fair chance of detecting a false negative case. False positive result can be seen in a lady taking HCG injections for infertility or for any other reason. Modern test kit is supplied with a paper strip impregnated with a chemical solution for detecting HCG. The kit also has a place to pour some urine sample. Usually the first morning sample is preferred. Positive test will show two bands in the examination area. And if the urine does not contain HCG, then there will be only one control band. The test will not take more than a few minutes and it is highly accurate (gives confirmatory result in 99% of cases). It is better to take less amount of water at night prior to the test, so the concentration of HCG will be higher in morning urine.
In the laboratory, urine sample is analyzed for presence of HCG. The test is called Beta-Gravindex tests. Although the technique is mostly similar, the test at the laboratory is done with some machines.
Blood samples are also analyzed in the laboratory to quantify the amount of HCG present in the sample. This is called Beta-HCG test. As little amount of HCG can also be demonstrated by this method (1mIU/ml), Beta-HCG test can give positive result as early as 6 days after conception.

For all practical purposes, detection of planned pregnancy can wait up to seven days of a missed conception. But academically pregnancy test can give positive results even after 48 hours of fertilization. The chemical marker for this test is called Early Pregnancy Factor (EPF). A test called RIA (Rosette Inhibition Assay) is done to detect the EPF. Although the test is very much accurate (99.5%), it takes about 3-4 hours for a single test and it is quite expensive. Therefore, use of this test is limited to some unprecedented conditions like sexual assault and when the victim feels that she can become pregnant (depending the date of menstruation).
Visualizing the uterus for presence of fetal sac by Ultrasonography (USG) can be done 2 weeks after conception using a transvaginal probe. After 5 weeks the fetus is visualized and the fetal measurements can be obtained. Fetal heart beat can be measured by USG only after 7 weeks of gestation.