All you need to do is simply pee on the test stick (or dip it into collected urine) and wait several minutes for your results. However, while home pregnancy tests are pretty simple to use, it’s very important that you carefully read the test directions. Accuracy depends on you correctly following the directions, including the timing of when to take the test and how to interpret the results. Learn more about how to use a home pregnancy test.

How Home Pregnancy Tests Work

Pregnancy tests work by detecting hCG (the pregnancy hormone) in your urine. When a fertilized egg has implanted into your uterus, your body will begin to make hCG. Most home pregnancy tests have about the same ability to detect hCG—they give a positive result if your hCG level is at least 20mIU (mIU is a level of measurement). Some home pregnancy tests are a little bit more sensitive and others a little less. Usually, the instructions tell you the sensitivity levels of the test.

When to Use a Test

A good rule of thumb is to wait at about 21 days (three weeks) after you last had unprotected sex/birth control failure before using a home pregnancy test—or at least one day after a missed period. On average, 20mIU/hCG levels are present about seven to ten days past ovulation. During a typical cycle:

Most people ovulate 14 or 15 days from the first day of their menstrual cycle. If the egg is not fertilized, then the next period should begin about 14 days after ovulation; these two 14-day spans make up a 28-day cycle. If the egg is fertilized, implantation generally happens at around 9 days (average 6 to 12 days) days after ovulation. Once implantation takes place, hCG will begin to be made (20 to 26 days into the cycle).

Before You Use a Test

Take these steps to get a home pregnancy test and prepare to use it.

How to Use a Home Pregnancy Test

Follow these tips on how to use a home pregnancy test. Firstly, take your test first thing in the morning. Your urine is more concentrated at this time. If you are pregnant, your first morning pee will have a higher amount of hCG in it than pee from later on in the day. To begin, wash your hands with warm water and soap. Remove the pregnancy test from its foil wrapper. Depending on the particular home pregnancy test, you should pee in a collection cup or pee directly onto the pregnancy test stick. Some tests will give you the option to collect your urine either way. It is important to catch a “midstream sample.” This means that you should let out a little bit of pee first, and then use the rest of your pee for the test.

If the test requires you to pee directly onto the stick, place the side of the test stick with the absorbent tip in your urine stream with the result window facing up. Pee on it for about 5 to 10 seconds (or whatever time it says in the directions).If you have collected your urine in a cup, use the supplied dropper to place a small amount of pee in the testing well. If your test did not provide a dropper but said that you could use a collection cup, dip the absorbent end of the pregnancy test into the cup of pee and hold in place for 5 to 10 seconds (or whatever time it says in the directions).

Place the pregnancy testing stick on a flat, dry surface with the “result window” facing up. The instructions will tell you how many minutes to wait for the results to appear. This can be anywhere from one minute to five minutes, though some home pregnancy tests can take up to 10 minutes to give you an accurate result. There will most likely be a “control window” on the test as well as a result window. You will probably see the background in the control window get darker as the urine passes through. Most control windows will display a line or symbol to show that the test is valid. If this control indicator does not appear, chances are very likely that the test is not valid or did not work properly. Once the required amount of time has passed, you can check the results. Keep in mind that different tests may display the results differently, so make sure you read in the instructions what shape or symbol you should be looking for. Examples include:

A pink or blue lineA red plus or minus signA color change in the window or in the urine in the testThe words “pregnant” or “not pregnant”

If any line, symbol, or sign shows up in the results window, no matter how faint, you can consider the home pregnancy test result to be positive. A line will not show up if the test does not detect hCG—so even the faintest line means that the test has picked up on hCG in your pee. If you got a positive test result on your home pregnancy test, it is important that you make a medical appointment. Your doctor can confirm the result of your home pregnancy test and begin prenatal care.

If Your Test Result Is Negative

If the home pregnancy test gives you a negative result, but you do not get your period, you should retest in 3 to 5 days. If you ovulated later in your cycle or did not properly calculate your ovulation date, you may have taken the pregnancy test too soon to receive a positive test result. Since the amount of hCG increases rapidly when you are pregnant, you may end up with a positive test just a few days after a negative one. This is why some home pregnancy test kits come with more than one test—so you have another one to re-test with. If you took your test fewer than 7 days after your missed period, do not automatically believe that a negative test result means that you are not pregnant. You may have taken the home pregnancy test too soon. Wait another week. If by that time you still have not gotten your period and are still getting a negative test result, you should make an appointment with your doctor to figure out if something may be going on.