What Are Evaporation Lines on a Pregnancy Test?

Pregnancy tests were designed to be user-friendly and accurate. However, things sometimes don’t work as expected.

In some instances, you may have evaporation lines on a pregnancy test, making it difficult for you to tell whether the result is positive or not.

Irrespective of whether you are trying to get pregnant or avoid a pregnancy, it can be distressing to have a result that you can’t interpret. Even when you suspect you might pregnant, you’ll still want to confirm it with a home pregnancy test.

Evaporation Lines on a Pregnancy Test: What They Mean

An evaporation line is a small streak that appears where you should have the positive line on a pregnancy test.

Sometimes, you can get a faint positive line on a pregnancy test. This is different from an evaporation line, which is typically appear as a colorless streak.

Why does an evaporation line appear?

You’ll get an evaporation line if you wait for longer than the time recommended to read the test result. It can also appear if you made the test wet or did not follow the instructions of the manufacturer when performing the test.

Contrary to a faint positive line that indicates a high probability of pregnancy, an evaporation line does not indicate that you are pregnant.

What to Do When an Evaporation Line Appears

No matter how distressing this can be, it is best not to worry when an evaporation appears. The best approach is to take another test.

Because an evaporation line can happen with any pregnancy test brand, do not rush to ditch your pregnancy test kit if you bought a packet that contains several test strips or sticks.

An evaporation line typically appears when a pregnancy test is negative or when the test was taken too early in the pregnancy to show a positive result.

How to Avoid Getting an Evaporation Line on a Pregnancy Test

Although evaporation lines are common, they do not happen every time you take a pregnancy test. However, they are more likely to appear if you do not follow the instructions on the packaging.

Here are some tips to avoid evaporation lines on a pregnancy test:

  1. If you’re not familiar with the test brand, read the instructions before performing the test.
  2. Use a cup or container to collect your urine before dipping the test in the urine sample for the duration specified in the instructions.
  3. Check your results within the time recommended by the manufacturer. It seems like a no-brainer, but it’s important that you read the instructions. If you have to read the results within two or five minutes, read it within the specified time for accurate results.
  4. Store your pregnancy test kit in a dry area. Most of us store it in the bathroom, which usually houses the shower and makes for a very humid and moist place to store anything.
  5. If you get a negative test result, toss it away. Do not be tempted to recheck the test strip or stick after ditching it into the garbage. The test may continue working after the window of opportunity to read the result, and you may be tempted to think the result turned positive hours later.
  6. Avoid drinking too much liquids before taking the test, as this might dilute your urine.
  7. Do not use an expired pregnancy test.

Is it an Evaporation Line or a Positive Test Result?

It is possible that you have an evaporation line in the following instances:

  • You read the results several minutes or hours after specified time interval.
  • You see a faint and colorless line where the positive where you should have the positive line.
  • The “line” has no visible dye in it.

It is possible that you have a positive test result (even if the test line is faint) in the following instances:

  • If you have missed your period or are experiencing early pregnancy symptoms.
  • You can see a visible dye in the line.
  • If you have used the test as described and the line appears within the time frame recommended by the manufacturer.
  • If you took an early result pregnancy test at least 11–12 days after ovulation.

Bottom Line

Home pregnancy tests are highly accurate, but you can have a false positive or negative test result if you do not follow the instructions on the package.

You might have a false negative test result if your take the test too early, including before the day of your expected period when your pregnancy hormone level (human chorionic gonadotropin or hCG) is too low to be detected by the test.

It can be distressing to wait for the results of a pregnancy test, whether you’re trying to get pregnant or avoid a pregnancy.

Either way, you should consider repeating the test if you’re not sure whether you’re seeing an evaporation line or a faint positive line. Your odds of being pregnant are higher if both tests show a line, even if it is a faint one.

If you’ve performed the test and read the results within the time specified on the packaging and are still unsure of the results, make sure the test has not expired and it was stored in a dry place.

Still unsure? Wait for a few days before repeating the test. It is preferable to repeat it on the day of your expected period or a few days after to reduce your chances of getting a false positive result.

If you do not wish to wait, visit your doctor so that they can perform a blood test, which will give you a reliable result, even at the earliest stage of pregnancy.


I’m Princila, founder of Check Ovulation and a proud mom of two. I’m an alumna of James Lind Institute. After working in clinical jobs, my passion for writing took its toll, and I ended up switching careers to work in the medical publishing industry. I also have a passion for healthy food, which prompted me to take several online courses in nutrition and health offered by Wageningen University. (I still haven’t completed the courses thanks to my busy mommy schedule!). When I’m not writing/editing scientific and medical manuscripts or taking care of my family, I use my free time to research, learn, and write about healthy living. I have also authored a few books in the self-help niche using the pen names Princila Murrell or PN Murray.

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