Do you think you may be pregnant? Here are a few tips about your pregnancy testing options...
What Is a Pregnancy Test?
Pregnancy tests detect a hormone called human chorionic gonadotropin (hCG) in a sample of urine or blood. This hormone HCG is produced by the placenta and is found in pregnant women. The amount of hCG produced during early pregnancy doubles every two or three days and peaks at 7-10 weeks. You can be tested for pregnancy with an over-the-counter pregnancy test or in your doctor's office.
How Soon After Conception Will a Home Pregnancy Test Work?
Some home pregnancy tests can detect pregnancy as early as one day after a missed menstrual period, although not all pregnancies will be picked up this early. Most home pregnancy tests are very accurate when done about a week after your first missed menstrual period.
How Are Pregnancy Tests Done at Home?
There are several different types of home pregnancy tests that are readily available at your local drug store. Because there are many brands, it is important to follow the directions on the individual package carefully.
Some tests require that you urinate directly on a stick, while others ask that you urinate in a cup and then place a small sample into a testing well with a dropper. The results can be as fast as a few minutes or as long as a several hours. Keep in mind that results are displayed differently with different tests as well. For example, some show a red plus or minus sign in a window, others show pink or blue lines on a test strip, while others change the color of a urine sample.
Once you get a result, you may begin to question the test's accuracy.
How Accurate Are Pregnancy Tests?
Home pregnancy tests are not 100% accurate. Many manufacturers claim to have a 99% accuracy rate, but inaccurate results may be more frequent. This is because of improper use of the test, using the test after its expiration date, exposure of the test to the sun, and other factors. Again, make sure to follow the directions of your particular test exactly as you are supposed to. This should help make the test more accurate.
After conception, a woman produces a minimal amount of hCG. Not all tests are strong enough to pick up the amount of hCG hormone present the first time. Later tests may be positive. Whatever the result or the brand used, most manufacturers recommend repeating the process several days later to confirm the results.
Other potential problems include:
- It is possible that you may get a negative test even if you are pregnant (false negative) if you take the test too early after conception, before hCG levels are significant.
- If you are taking medications that has hCG in them, you may get a positive test even if you are not pregnant (false positive).
How Are Pregnancy Tests Conducted in a Medical Office?
Either a urine test or blood test is available at your doctor's office or a family planning clinic. For the urine test, a urine sample is taken, usually first thing in the morning.
A blood hCG test involves taking a sample of blood from a vein in the arm. A blood test may be ordered to measure how much hCG is in the blood. The blood test can detect a pregnancy earlier than the urine test. Results of these pregnancy tests may be available the same day they are administered.
If your test is positive, make sure you follow up with your doctor right away. You cannot start prenatal care too soon.
- Reviewer: Brian Randall, MD
- Review Date: 12/2012 -
- Update Date: 12/11/2012 -