The fertilized egg plants itself on the wall of the uterus and placenta forms. This then starts secreting a unique hormone called the HCG or Human Chronic Gonadotropin.
This hormone is secreted 4-6 days after the first missed period. The number of days taken may vary. Each pregnancy test detects this hormone.

First of all let me tell you about these tests. There are two types of pregnancy tests

1) Urine Pregnancy Test.
2) Pregnancy Blood Test

What is Home/Urine Pregnancy Test?
The home/urine pregnancy test kits are available in any retail store or a medical outlet. You can say this is the easiest way to find out whether you are pregnant. This home pregnancy test also guarantees you privacy just in case you do not want to let anyone know about your pregnancy. This test is also clean and hygienic.

What are Pregnancy Test Kits?
The pregnancy test kit has strips on which there is a chemical which detects the hormone HCG. Some kits have two lines some have a positive or negative sign on them.
However, before buying a home pregnancy test kit make sure that it is within its validity date. Ditto, with the ones which have been lying in your home for a long time. Checking validity date of pregnancy test kit is important. A pregnancy test kit past its validity date will not give you the correct results. Buying bulk urine pregnancy test kits works out to be lot cheaper than the retail kits.

How does a Urine Pregnancy Test Work?

Each manufacturer gives different instructions about how to use the kit. Following instructions is the important part of this test. Any deviation from instructions can yield incorrect results. Some might ask you to pee directly on the test strip whereas others will ask you to first take some urine in a clean cup or bowl and use a dropper to put a few drops or urine on the strip.

If you are pregnant, both lines on the strip will change color, after urine has been put on it. Incase of strips with positive or negative signs, if the positive sign shows, that means you are pregnant and if the negative sign shows that means you are not pregnant.

Which Urine sample is the best for test?

Urine at any time cannot be used as a sample for the urine pregnancy test. It is very important to know which urine should be taken as sample. First morning urine should be used ideally as the sample urine for the test.
HCG takes time to accumulate in urine. Therefore, this test required concentrated urine sample. If the test requires to be done in day time, see to it that you do not urinate for 4-5 hours before using this urine as sample.