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What Are Evaporation Lines?

Yes, a line is indeed a line on a pregnancy test, whether dark, light, thick, or thin. A second line means that you are, in fact, 100% pregnant!

Wrong! While some of us are veterans of trying to conceive and know the ins and outs, others may not be as familiar with this type of stuff. So when isn’t a line and line on a pregnancy test? The answer to this question is evaporation lines.


What Are Evaporation Lines?
How do you know if it’s an evaporation line?

What Is An Evaporation Line?

An evaporation line on a pregnancy test is caused by the evaporation of urine on the test area, causing a false-positive result. An evaporation line may be caused by waiting too long and reading the result after the time limit. Although the time limit is usually the culprit for creating an evaporation line, it is not always the cause and an evaporation line may develop even within the time limit.

So, is a line a line, and I am pregnant? Or is a line an evaporation line, and I am not pregnant? Hmm, kind of confused here.

An evaporation line does not indicate that a woman is pregnant. When an evaporation line appears, it is best to take another test for an accurate result. 

Tips to reduce evaporation lines

So how do you tell if it’s an evaporation line or a real line? First, you can use pink dye pregnancy tests rather than blue dye pregnancy tests. The blue dye tests are more likely to give you an evaporation line than the pink dye tests.

You can also only read the result within the time limit! Each brand of pregnancy test should indicate on the box when the test results should be read. It is usually somewhere under 10 minutes with the Fertility2Family tests. You need to leave the test for 3 minutes; after this period, the results will be ready to read. Do not interpret test results after the time limit. Reading the result after this time frame allows the urine time to evaporate on the test resulting in, yes, you guessed it, an evaporation line!

Evaporation line or a positive result

Study the line closely. Does it have colour to it? Or is it more of a grey, a white or an indent? Or is it an evaporation line? A positive pregnancy test result should be pink (or blue), just like the control line. It should also run from the top of the test window to the bottom of the test window. And have the same thickness as the control line. So basically, the test line needs to look like the control line, but it does not need to be as dark as the control line.

Another tip to avoid the dreaded evaporation line is to dispose of damaged or expired tests. They cannot be trusted!

Evaporation Lines
Evaporation Lines and Fertility2Family

A mark on a pregnancy test may be an evaporation line if:

  • More than 10 minutes have passed since taking the test.
  • The mark is faint and colourless, and it resembles a water spot.
  • The mark has no visible dye in it.

If the control line on the test does not change colour, the test has failed.

A line on a pregnancy test may show a positive result if:

  • A visible dye is in the line, even if the colour is faint.
  • The line appears within the period specified on the instructions, usually 3–5 minutes.
  • A woman has taken an early-result test at least 11 days after ovulation.
  • A woman has taken a regular test at least 14 days after ovulation.
  • A woman has missed her period.

How Do You Decrease The Chances Of Seeing Evaporation Lines?

  • Don’t test too early. The earlier you test, the lowest your hormone (hCG) levels will be. If you have a real squinter, test again in a day or two. As hCG rises, an actual positive test will darken. Testing early and waiting longer for the results can increase the chance of evaporation lines.
  • Take a more sensitive test. Different test types and brands have different hCG thresholds to display a positive result. Because of this, cheap tests that you order online (such as Fertility2Family tests) are more reliable when you test early than digital tests. Remember that the downside of testing early is that you are more likely to find out if you have a chemical pregnancy. These very early miscarriages are pretty common. They usually do not signify any kind of underlying fertility problem. Before the advent of susceptible pregnancy tests, women might have had chemical pregnancies without realising it.
  • Don’t overhydrate. If you have been drinking a lot of water and urinating frequently, your urine may be too dilute for an accurate reading and this may cause an evaporation line. It’s best to hold your urine for two or three hours to ensure it is not too diluted. First-morning urine is usually more concentrated than urine from random hours during the day.
  • Try urinating in a cup before taking the test, then dipping the test in the urine for the duration specified on the packet. This technique prevents too much urine from splashing onto the test.
  • Do not use a pregnancy test that is past its expiration date.
  • Avoid storing pregnancy tests in very hot or cold locations.

Results of a pregnancy test

Waiting for the results of a pregnancy test can be agonising. A simple way to help ensure accuracy is to take two tests. If both show a line, even a faint one, the result is likely positive.

Anyone unsure of the results should give hCG levels time to rise and take another test in a few days. This can reduce the risk of false negatives.

A doctor can provide the most accurate results by testing blood or urine.

Evaporation Line FAQ


Can an evaporation line be mistaken for a positive result?
An evaporation line can be mistaken for a positive result, especially if the test is read after the suggested time limit. However, an evaporation line is typically colourless, unlike a positive result, which will have colour. Taking another test is recommended if there’s any doubt about the result.
How common are evaporation lines on pregnancy tests?
Evaporation lines are not uncommon on pregnancy tests, especially if the test is read after the suggested time limit or if the test gets wet. However, they do not indicate pregnancy. it’s advised to strictly follow the instructions on the pregnancy test kit to avoid confusion due to evaporation lines.
Can you prevent evaporation lines on a pregnancy test?
Yes, you can prevent evaporation lines by strictly following the instructions on the pregnancy test kit. This includes reading the result within the specified time limit and ensuring the test doesn’t get wet. Using a new test that has not passed its expiration date is also recommended.
Can an evaporation line appear on any brand of pregnancy test?
Yes, an evaporation line can appear on any brand of pregnancy test if the test is read after the suggested time limit or if the test gets wet. However, some brands may be more prone to evaporation lines than others. Using reliable and high-quality pregnancy test kits is recommended to ensure accurate results.
Can the colour of the evaporation line vary?
Typically, an evaporation line is colourless. However, depending on the test and the lighting, it may sometimes appear as a faint grey or white line. It’s important to note that a positive result will have colour, even if it’s faint. If you need clarification on the line’s colour in Australia, taking another test to confirm the result is recommended.
Can an evaporation line show up within the time limit?
While less common, an evaporation line can sometimes appear within the time limit. This can happen if the test gets overly wet. In Australia, following the instructions carefully and avoiding over-saturating the test is recommended to prevent this.
Does the thickness of the evaporation line matter?
An evaporation line is typically thinner than a positive line. However, the thickness can vary depending on the test. If you’re unsure about the thickness of the line, taking another test to confirm the result is recommended.
Can an evaporation line disappear?
An evaporation line can disappear over time as the test dries out. This is another reason why reading the test within the specified time limit is important. Discarding the test after reading the result is recommended to avoid confusion later.
Can an evaporation line appear on a digital pregnancy test?
Digital pregnancy tests typically display words like “pregnant” or “not pregnant,” so they don’t have EVAP lines. However, they can sometimes show false-positive or false-negative results due to other factors. In Australia, following the instructions carefully when using digital pregnancy tests to ensure accurate results is recommended.
Can the time of day affect the accuracy of a pregnancy test?
Yes, the time of day can affect the accuracy of a pregnancy test. The concentration of hCG, the hormone detected by pregnancy tests, is usually highest in the first urine of the day. Therefore, testing first thing in the morning can increase the accuracy of the result. In Australia, it’s common advice to use the first-morning urine for pregnancy testing, especially if testing early.
What should I do if I get different results on different pregnancy tests?
If you get different results on different pregnancy tests, taking another test a few days later is recommended. This is because the hCG levels in your body double approximately every 48 to 72 hours during early pregnancy. Therefore, testing again after a few days can give a more accurate result. In Australia, it’s common advice to repeat the test if you get inconsistent results.

A trusted partner in your fertility journey

Understanding the complexities of pregnancy tests, including evaporation lines, can be confusing and stressful. That’s why Fertility2Family is committed to providing accurate, easy-to-understand information and quality products to support your fertility journey. Our range extends beyond pregnancy and ovulation tests to include various resources and expert advice on fertility topics. Authored by professionals in the field, our articles and how-to guides are designed to ease your worries and arm you with the essential information for making well-considered choices. With Fertility2Family, you’re not just buying a product but gaining a trusted partner in your fertility journey.


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Evan Kurzyp
Evan is the founder of Fertility2Family and is passionate about fertility education & providing affordable products to help people in their fertility journey. Evan is a qualified enrolled nurse and has expertise in guiding & managing patients through their fertility journeys.

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