How You Can Avoid Evaporation Lines on Pregnancy Tests (2024)

FAQs

How You Can Avoid Evaporation Lines on Pregnancy Tests? ›

Follow the Instructions

To prevent evaporation lines: Try urinating in a cup before taking the test, then dipping the test in the urine for the duration specified on the box. This technique prevents too much urine from splashing onto the test.

“The best way to avoid an evaporation line is to check the results of a urine pregnancy test within five to 10 minutes of conducting the test and avoid drinking a large amount of water,” Burroughs says, since that can dilute the urine and skew results.

An evaporation line is a faint, colorless line that appears in the results window of an at-home pregnancy test. This happens if the urine being tested has dried beyond the reaction time of the test.

Your urine is too diluted

A very faint line may also happen if your pee is too diluted to detect hCG, which can happen when you've been drinking fluids throughout the day. That's why taking a pregnancy test first thing in the morning when your pee is more concentrated might give you a clearer result.

Increasing water salinity reduces evaporation since the dissolved salt ions lower the free energy of the water molecules, i.e., reduce the water activity, and hence reduce the saturation vapor pressure above the saline water at a given water temperature (Harbeck, 1955; Lee, 1927; Salhotra et al., 1985; Stumm & Morgan, ...

Evaporation lines are common and can occur with any pregnancy test. An evaporation line is a line that appears in the results window of a pregnancy test as the urine dries. It can leave a faint, colorless line. If you're not familiar with evaporation lines, you might see this line and think you're pregnant.

Evaporation lines are relatively common, and they might appear on a pregnancy test as the urine dries. They typically show up after the timeframe where you're instructed to read the results—which is generally from two to five minutes after you pee on the stick.

You might want to take your mind off the nervous wait, but don't wander off and forget; leaving the test 'cooking' for too long can give a false positive result. The reason for this is due to the urine evaporating if left for too long; it can leave a faint line which can be mistaken as a positive test.

Any positive line, no matter how faint, means your result is pregnant. Levels of hCG in your body will increase over the course of your pregnancy. If you test early, your hCG levels may be still be low and you'll see a faint positive line.

What color are EVAP lines? ›

"It's sometimes hard!" says Dr. Alrahmani. While a true positive pregnancy test will contain some color, an evap line will be colorless. "Evap lines may be fainter, and in a different spot than where you would expect the pregnancy test [results]," she explains.

They generally double every 24 hours during the first 8 weeks, peak around 10 weeks, and then decrease. 2 Considering that pregnancy tests detect hCG in your urine, it's normal for the test line to get darker as your first trimester progresses.

Interpreting Pregnancy Test Results

Sometimes you'll see a faint line if you test on the earlier side and the hCG is still building up in your system. A line that gets progressively fainter over days of testing may indicate that you're miscarrying, so reach out to your provider if this happens.

If the line on your test tomorrow becomes darker and more clear, then you can be confident it's a positive pregnancy test and not an evaporation line.

You're Pregnant—But There's Not Enough hCG in Your Urine Yet

A faint line could very well indicate that the urine used for the sample is pretty diluted, or that it's very early in the pregnancy—there is just enough hCG to turn the test positive, says Woeber.

Evaporation lines are relatively common, and they might appear on a pregnancy test as the urine dries. They typically show up after the timeframe where you're instructed to read the results—which is generally from two to five minutes after you pee on the stick.

If you want to save time and money, your best bet is to wait longer than 12 hours before taking another pregnancy test. But there are a couple of scenarios in which 12 hours might make a difference: Your hCG level just happens to cross over your test's sensitivity threshold during that 12-hour time period.

In many cases, you might get a positive result from an at-home test as early as 10 days after conception. For a more accurate result, wait until after you've missed your period to take a test. Remember, if you take a test too soon, it could be negative even if you're pregnant.