Pregnancy Tests

Whether you're trying to get pregnant or trying not to, a home pregnancy test offers a fast and reliable way to find out where you stand. When used properly, most over-the-counter pregnancy tests are accurate about 99 percent of the time.

All the test kits sold for home use are designed to detect small amounts of human chorionic gonadotropin (HCG)—a hormone produced by a fertilized egg within one to two weeks after conception. Home tests use specially treated strips that react to the presence of HCG in female urine. A positive result (in other words: "You're pregnant!") is indicated when the strip changes color or shows a plus sign or some other symbol.

How to choose a Pregnancy Test

There are a lot of different brands to choose from. Virtually all are competitively priced and easy to use, providing fairly quick results—within one to five minutes. The following factors may guide your choice:

• The fewer the steps, the less chance for error on your part. One-step tests that require you to hold a test stick under your urine stream are the easiest.
• Some tests require you first to collect your urine in a cup. Then, depending on the test, you either dip the test stick into the cup, or using a dropper, add your urine to a well on the end of the test stick.
• If cost is a concern, opt for generic or less well-known brands, which provide the same reliable results as heavily advertised brands.
• Some manufacturers sell two tests in one box. If you think you might be testing more than once, buying a double kit is more cost-effective.

How to use a Pregnancy Test

Most kits can be used as soon as the first day after a missed period. If you use the test as directed, you're virtually assured of an accurate result. But studies show that people don't always use the tests properly. So even one-step tests start with an extra step: reading the package instructions carefully.

Before you take the test:

• Check your calendar: You need to wait until your period is at least a day late before getting an accurate test result.
• Check the kit's expiration date. An outdated test may not produce accurate results.
• Make sure the kit has been properly stored. If exposed to high temperatures (for example, if you leave the kit in a sunny window), the chemicals on the test stick may be compromised.
• Avoid drinking large amounts of any liquid before you take the test. Fluids can dilute the hormone in the urine, making it more difficult to detect.

Here's how to take the test:

• Remove the test stick from its packaging just before taking the test, but not earlier.
• For one-step tests, hold one end of the test stick between your thumb and forefinger, and place the other end under your urine stream for a few seconds as directed. Place the test stick on a flat surface with the results window facing up.
• For tests that require urine collection, always use the collection device (usually a plastic cup) provided in the kit, and test the sample immediately after collection.
• Check for results as soon as directed in the instructions. If you check too soon or wait too long after the test, the results you see may not be accurate.
• If the results are positive, consult a doctor immediately.
• If you believe the results are incorrect, think back over your methods and try to identify places where an error might have happened in the testing process.
• Before performing a second test, wait the number of days suggested by the test manufacturer. After a second test, if you still believe the result is incorrect, consult your physician.