If a woman gets pregnant, her body will start to produce the pregnancy hormone 'hcg', which is short for 'human chorionic gonadotrophin'. This hormone can be found in the blood very soon after conception takes place.

Hpt's work by detecting the presence of hcg in the woman's system. A blood test done in a lab is the most sensitive method of detecting a pregnancy, although home pregnancy tests that measure the hcg in the urine can be quite sensitive too.

If you are going to use a urine test, it is usually recommended to wait until you have missed your period so that the hcg has enough time to build up in your system in order to be detected. If you just can't wait, a blood test can be taken a few days before your period is due, and still show a positive result.

How Home Pregnancy Tests Work, and How to Use Them

Using hpt's involves urinating for a few seconds on a 'test strip' portion of the tester. If this seems difficult, you can instead pee in a cup and hold the test strip in the urine for a few seconds.

After the allotted wait time has passed (each pregnancy test company will dictate the amount of time necessary to wait on their instructions), the results window will show either a positive or negative sign. A positive result can be shown either as a double line, a plus sign or a happy face. These positive signals are caused by the monoclonal antibodies in the tester reacting with the hcg in the urine.

It is very important to read the instructions of the hpt carefully. Aside from urinating on the test strip for the recommended number of seconds, and waiting the allotted time before reading the results, it is important to take notice of the test reading time. After a certain amount of time has passed, the test result is no longer accurate. If a positive result is read hours after the test was taken, the test cannot be taken seriously. What may be showing is an evaporation line that occurs as the urine dries on the tester.

Waiting until you have missed your period will increase the accuracy of the test. If you test too early, and you are pregnant, the tester may come out negative because there is not enough hcg in your system yet for it to be detected by the home pregnancy test.

Try to test first thing in the morning. This is because the urine is most concentrated at that time, which means the hcg will also be more concentrated.

False Positives and False Negatives

False positive results are pretty rare. This can be caused by incorrect use of the pregnancy test, or by the use of fertility drugs such as Clomid.

False negative results are a bit more common. This due to factors that were discussed above. Testing before a missed period and using mid-day urine that is not hcg-concentrated are the biggest reasons for this.

Home pregnancy tests are about 97% accurate. But if you simply cannot wait, get a blood test done and find out for sure!

Find home pregnancy tests online by clicking here .