McKesson Clinical Reference Systems: Women's Health Advisor 2002.2
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What is a pregnancy test?

You can find out if you are pregnant with tests of your urine or blood. These tests look for a hormone called human chorionic gonadotropin (HCG). HCG is produced by the placenta. It is found in your blood or urine only when you are pregnant.

Pregnancy tests can be done at home or at your health care provider's office.

How soon can I use a home test to see if I am pregnant?

Some home tests can be done as soon as the day your period should have started. The tests will be more accurate, however, if they are done 2 weeks after the day your period should have started.

How are pregnancy tests done at home?

Carefully follow the instructions that come with the test kit. Collect a sample of your urine the first time you go to the bathroom in the morning before you have had anything to drink. In most tests you then add the urine to a chemical solution in a test tube or on a glass slide. You will know the results in 2 minutes to 2 hours, depending on the test kit you use.

If the test is positive there is a good chance that you are pregnant. Make an appointment with your health care provider to confirm the test result.

If the test is negative and you had your last period less than 6 weeks ago, repeat the test in 1 or 2 weeks. If the test is still negative, you are probably not pregnant. Something else may be causing you to miss your periods. If your period is 6 to 8 weeks late, you should see your health care provider even though the test is negative.

Home tests are never 100% accurate. You may get a positive test result even though you are not pregnant if:

• You are going through menopause.
• You are taking antidepressant drugs.
• You have had an ovary removed.
• You have kidney problems.
• You have hyperthyroidism (overactive thyroid gland).

You should see your health care provider to confirm a positive home test result.

How are pregnancy tests done at my health care provider's office?

You may get a more reliable urine test for pregnancy at your health care provider's office or a family planning clinic. These tests may not be any more expensive than a home test kit. You may know the test results the same day.

With a blood test your health care provider can find out if you are pregnant as early as 9 days after a baby is conceived. The blood test measures the HCG level in your blood. It is called a radioimmunoassay (RIA). The test takes about 45 minutes to run and is more expensive than a urine test. The results should be ready in a few hours.

This content is reviewed periodically and is subject to change as new health information becomes available. The information is intended to inform and educate and is not a replacement for medical evaluation, advice, diagnosis or treatment by a healthcare professional.