Patient education: Pregnancy tests (The Basics)

What is a pregnancy test? — This is a test that can show if a person is pregnant. It checks urine or blood for a hormone called "human chorionic gonadotropin," or "hCG." The placenta makes this hormone during pregnancy. In a normal pregnancy, the level should rise quickly over the first 4 to 10 weeks.

There are 3 types of pregnancy tests:

●In-office urine test – This is done in a doctor's office or clinic. If you have more than a certain level of hCG in your urine, the test will be positive.

●Home pregnancy test – This is also done on a urine sample. You can buy different test kits to use at home. Some are more accurate than others.

●Blood test – You need to have a small amount of blood taken for testing. The blood draw can be done in a doctor's office, clinic, or hospital. Some blood tests just give a positive or negative result. Others measure the exact amount of hCG in your blood. This can help your doctor see how your hCG level changes over time.

Which test is best? — It depends on several different things. These include convenience, cost, and timing.

●An in-office urine test is the most common way doctors check for pregnancy. These tests give results right away. They can be done on a urine sample at any time of day.

●A home pregnancy test is often the most convenient and gives results quickly. But these tests cannot always find very low levels of hCG. So they are sometimes negative very early in pregnancy, before hCG levels have increased a lot. Also, a positive home pregnancy test might need to be confirmed by a doctor or nurse by repeat testing.

●A blood test can show if a person is pregnant earlier than a urine test. It is also the best way to measure the level of hCG, if your doctor needs to know this. But it requires getting a blood draw, and it sometimes takes a while to get results back from the lab.

How do I do a home pregnancy test? — Different home test kits come with different instructions. Follow the instructions carefully to get the most accurate result.

In general, you should:

●Know when to take the test – Many home pregnancy tests work well if used on or after the date of your first missed period. But this is not the same for all tests. If you test too early, your body might not be making enough hCG to show up on the test yet, even if you are pregnant.

●Test a urine sample – You might collect your urine in a cup, then dip the test stick or strip into it. Or you might hold the test stick in your urine stream for a few seconds. Some tests suggest using a urine sample from first thing in the morning.

●Wait for the results – This usually takes a few minutes. Results might appear as a symbol, a color, words, or lines. Make sure that you understand whether your result is positive or negative.

What do my results mean? — If you had a pregnancy test in a doctor's office or clinic, your doctor or nurse will tell you when to expect your results. Or if you use an online "patient portal," you might get an alert there when your results are ready.

In general, the result of any pregnancy test will be either positive or negative:

●Positive – Most of the time, a positive result means that you are pregnant. Rarely, it is possible to get a "false positive," meaning that the test came back positive but you are not actually pregnant. For example, this could happen if you have a health condition that causes your body to make hCG. A test could also be positive for a short time after an early pregnancy loss (miscarriage).

●Negative – This means that the test did not find a certain level of hCG in your blood or urine. Most of the time, a negative result means that you are not pregnant. But it is possible to get a negative result if the test was done very early in pregnancy. That's because tests cannot always find very low levels of hCG. If your test is negative but you might be pregnant, your doctor will probably have you do another test in 1 week.

Some blood tests measure the level of hCG in your blood. This is reported as a number. A result over a certain number is considered positive. In some cases, your doctor might want to repeat this test a few days later to see how your hCG level changes over time.

What else should I know? — If you think that you might be pregnant, tell your doctor or nurse. They will tell you if you should make an appointment or come in for a urine or blood test.

If you are pregnant, your doctor or nurse will talk to you about planning your care.

More on this topic

Patient education: Pregnancy symptoms (The Basics)
Patient education: Prenatal care (The Basics)