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Can you mess up a pregnancy test?

Can you mess up a pregnancy test?

With their convenience and ease of use, home pregnancy tests have empowered women immeasurably by providing accurate, clear answers quickly. However, many women, whether they want to be pregnant or not, are nervous when testing. And that fluttery feeling can sometimes spur fluttery thoughts: Will I make a mistake? Am I doing this right?

Most home pregnancy tests (HPTs) are easy to use by design. As long as you read and follow the instruction insert, you can feel confident the test was taken correctly. Here we offer some tips for avoiding common mistakes while testing, and offer some helpful resources, too.

Can you take a pregnancy test wrong? Five ways to avoid mistakes

1. Read the instructions

You may be thinking, But all HPTs are basically the same — you just pee on a stick and wait. Not exactly. Each brand and type of home pregnancy test comes with a specific set of instructions that you should read before taking a test.

The instruction insert provides a wealth of information, including how early you can test, how far you should place the tip in a urine sample, what position the test stick should be kept in, how long you should sample for, how long you should wait before reading the results, and how to read those results.

The instruction insert also can answer many of your questions, including:

  • How early can I test?
  • My result is “Pregnant.” What should I do?
  • My result is “Not Pregnant.” What does this mean?
  • How does the test work?
  • When should I read my result?
  • Can any medications or medical conditions affect my test results?
  • Will the amount of liquid I drink affect my test results?

To download instruction inserts for any Clearblue® pregnancy test, visit our guide on how to take a pregnancy test.

2. Take the test at the optimal time

Waiting is one of the hardest parts, right? Whether you’re trying to conceive or not, this huge question (“Am I pregnant?”) looms — heavily, excitedly or anxiously, depending on your circumstance — until you know for sure. But if you test too early, all you’re likely doing is wasting a test.

Here’s why: The pregnancy hormone human Chorionic Gonadotropin (hCG) doesn’t start appearing in urine until after a fertilized egg implants in your uterine wall, typically six to eight days before the missed period. At first the amount of hCG in the mothers’ urine is very low and undetectable by home pregnancy tests, but during the first eight weeks of pregnancy, it typically doubles about every 24 hours.1

If you use an early detection pregnancy test, hCG can be detected in your urine a few days sooner than your missed period. Depending on the product, this could be up to six days before your missed period (which is five days before you expect your period).

Let’s break this down a bit more: If you expect your period to arrive on the 10th day of the month, the 10th is the day of your expected period and the 11th is the day of your missed period. Therefore, with a “six day early test,” for instance, you could test on the 5th, which is five days before your expected period and six days before your missed period.

Your test’s instruction insert will help you determine what day you can start testing. Our online calculator also can help. And the Clearblue® Advanced Period Tracker is a really useful tool to help you track your periods.

3. Read the results within the test’s result window

You probably know that you have to wait a certain amount of time before you can read the results of your pregnancy test. But did you know every test has a window of time in which the results can be read? Here are some examples:

  • Clearblue® Early Detection Pregnancy Test:
    The test result should be read as soon as possible after waiting for 3 minutes. Test results should not be read after 5 minutes.
  • Clearblue® Rapid Detection Pregnancy Test:
    A “Pregnant” result may appear as fast as 1 minute when testing from the day of your missed period. You should wait 3 minutes to confirm a “Not Pregnant” result, or when testing before you have missed your period. Read your result within 10 minutes of testing and disregard any changes after this time.
  • Clearblue® Digital Pregnancy Test with Smart Countdown:
    The Smart Countdown will finish in 1-3 minutes and your result will be displayed on screen in words. A “Pregnant” result stays on screen for up to six months. A “Not Pregnant” result stays on screen for approximately 24 hours.

This again illustrates the importance of the instruction insert. If you’ve lost the insert or accidentally threw it away, remember that you can access instruction inserts for any Clearblue® pregnancy test here.

4. Avoid drinking too much liquid before taking the test

This is an easy mistake to make. Maybe you bought your pregnancy test on the way home from work and you’re eager to test. Or perhaps you were lying in bed, unable to sleep, and suddenly thought, When was my last period? Or maybe you woke up and drank two cups of coffee before you remembered: It’s testing day! In each of these scenarios, if your period isn’t due yet, it’s better to wait and test the next day, using your first morning urine. If you’re testing any day from the day of your expected period or onward, it’s best to wait until you naturally need to pee again.

Why? Drinking lots of liquid before testing dilutes the amount of hCG in your urine, making it harder for the test to detect. This is even more important when testing early, as the amount of hCG is already even lower — so it’s best to test with your first urine of the day.

If you got a negative pregnancy test result — and you drank an excessive amount of fluids before you took the test — you should consider taking another test later.

5. Checking the expiration date

It comes as a surprise to many people that pregnancy tests expire. The antibodies used in home pregnancy tests aren’t as good at detecting hCG once a test hits its expiration date (typically one to three years after it was manufactured). All Clearblue® pregnancy tests have clearly marked expiration dates on the bottom of the box and on the foil wrapper of each test.

It’s important to check the expiration date every time you test. The expiration date is based on when the test was manufactured, not when you purchased it, so it may be sooner than you expect.

Do expired pregnancy tests work? We don’t recommend using them. Since an expired test may not be able to detect hCG levels that a nonexpired pregnancy test could, it could lead to a false negative result.

Can pregnancy tests be wrong?

Even if you didn’t follow your home pregnancy test instructions exactly, know this: A false positive is rare. All Clearblue® pregnancy tests are over 99% accurate from the day you expect your period.2 False positives can occur if you’re taking fertility medications that contain hCG, if you have a rare medical condition (such as an ovarian cyst) or if you’ve recently had a birth, miscarriage or termination. Some women may get a positive result and then experience early pregnancy loss. This is a real pregnancy that did not continue — not a false positive.

On the flip side, a negative result doesn’t necessarily mean you’re not pregnant. If testing early, your hCG levels may be too low for the test to detect. You also may have calculated the date of your expected period incorrectly. Drinking too much liquid before testing, using an expired test or not storing it properly (pregnancy tests should be stored between 36° and 86°F) can also result in a false negative.

If you think you’re pregnant but the test result is negative and you tested early, test again on the day you expect your period. If you think you’re pregnant, the test result is negative and you’ve tested from the day of your expected period, test again three days later. If the result is still negative, talk to your doctor.

So, yes, you can take a pregnancy test wrong — but it’s not likely if you follow the instructions carefully. Home pregnancy tests are designed with the knowledge that they are used during an often emotionally charged time, when you may be more focused on what’s to come versus the next step in a set of instructions.

Take a breath, and make sure you read the instructions. You’ve got this.


  1. Betz, D., & Fane, K., (August 11, 2021), Human Chorionic Gonadotropin [E-book], StatPearls, https://www.ncbi.nlm.nih.gov/books/NBK532950/.

  2. >99% accurate at detecting typical pregnancy hormone levels. Note that hormone levels vary. See insert.