Learn about the basics of testing for pregnancy at home
A missed menstrual period or two can be indicative of pregnancy and many women prefer to use a home pregnancy test that allows them to conveniently check this in the privacy of their home. Especially when this test shows a positive result for pregnancy, it is advisable to follow it up with a laboratory test performed using a blood sample.
Principle of Home Pregnancy Tests
When a woman conceives, her body secretes a hormone called human chorionic gonadotropin or hCG which appears in the urine after around 14 days of conception. On reaction with the reagents present in the home pregnancy test kit, a colour forms, indicating the presence of the hormone and this is taken as a positive identification of pregnancy.
Types of Test Kits
Home pregnancy test kits are generally of three types. One is a strip that you have to hold in such a way that the urine falls on it as you urinate. The other type requires you to collect the urine sample in a cup and then dip the strip into it. Some tests have a small opening into which you have to place a drop of urine using a dropper.
Performing the Test
The test is best done with the first early morning sample of urine. All you need to do is take a single drop of urine using the dropper provided with the kit and place it in the specified area of the strip. Over the next minute or two, the urine sample moves across the chemical reagents embedded into the strip, and indicates presence of the hormone by formation of a specific colour.
Tips to Ensure Best Results
When you strictly follow the instructions printed on the pregnancy test kit, you have a better chance of avoiding erroneous results. At the time of buying the kit, make sure it has not crossed the expiry date specified on the pack. Find the package insert that accompanies the product and read the instructions it carries carefully before using it. Understand the correct time and way of collecting the urine sample and adding it to the test strip. Read carefully the instructions about interpreting the test so that you do not draw the wrong conclusions.
Validity of Test Results
Like any other test, home pregnancy tests are also subject to the risk of a wrong result which can be one of two types: false positive and false negative.
A false positive means the test result shows you are pregnant whereas actually you are not. A false negative is the opposite – the result shows you are not pregnant although you are. This is the reason why doctors recommend laboratory testing on a sample of blood to arrive at a valid result. To lower chances of an erroneous result, it is important you allow enough time – at least a week or two – to elapse following the missed period.
This is because the concentration of hCG produced and excreted in the urine keeps increasing as the pregnancy proceeds. An early morning urine sample has a greater concentration of hCG and therefore, is more likely to provide accurate results. In the event that you find the result shows negative, you may repeat the test after another week or two using a new kit.
The pregnancy test kit only gives you a yes/no answer; it cannot tell how much of the hormone is present in the body, nor can it give information about whether the pregnancy is developing normally. Therefore, make it a point to consult your gynaecologist after you obtain the results.