Positive pregnancy test or evaporation line?
By Lindsay Meisel | Published Jun 6, 2018 | Last updated Oct 10, 2018 ✓ Checked for fact
Medically checked by on
Oh, that irritating resemblance between a positive pregnancy test and an evaporation line! Have you ever tossed a negative pregnancy test in the trash and looked at it hours later – and was shocked to see a second line? Then you know what we’re talking about. In most cases this is actually not a positive result, but rather a very cruel and confusing phenomenon known as the evaporation line.
You already know when to take a pregnancy test and how to find the best pregnancy tests. But do you also know how to make sure that the second line is really a positive result? To better understand why lines of evaporation occur and how to avoid them, let’s first take a look at the anatomy of a pregnancy test.
How do pregnancy tests work?
There are three types of home pregnancy tests: medium flow tests, immersion tests, and pipette tests.
- Medium flow tests: hold these in the urine flow for a few seconds and then wait a few minutes for the results.
- Immersion Tests: Pee in a cup, and then dip the test (usually in the form of a strip) into the cup.
- Pipette tests: In this type of test, fresh urine, which has previously been taken from a beaker with a pipette, is dripped into a test dish.
In any of these tests, the most important step is to read the instructions first. Different tests have different instructions, and sometimes the same pack contains more than one type of test and the instructions differ slightly from test to test. So be sure to read the instructions so you don’t waste a drop of urine!
When the waiting time is up, look at the results window to see if the test was positive or negative. Positive tests display a plus sign, two lines, or an explicit message such as “pregnant” or “yes”.
The tests that show the result by two lines have two hidden “indented” lines where the ink will accumulate: one for the control line and one for a potentially positive result. As the ink moves across the results window, it will build up in one or both of the indentations.
What is an evaporation line and how is it different from a positive pregnancy test?
An evaporation line (also called an evaporation line) is a pale line that appears after a negative test dries up. Tests are usually intended to be read three to five minutes after they are run, while they are still wet. After this time, the urine dries in the test. As the ink wanders across the screen, the result becomes visible. Sometimes a little ink gets caught in the indented line as it wanders across the screen, which is not intended. As the test dries up and the urine evaporates, this ink will pull towards the surface and darken.
Therefore, the most important rule if you want to know for sure whether the pregnancy test was positive is: Only read it within the allotted time! The results are only reliable within the time span specified in the instructions.
How do you distinguish a pale positive test result from an evaporation line?
Well, now you know how to spot a false positive test result. But what if you see a faint line within the time allotted for the test? How do you know the pregnancy test was really positive?
- Don’t test too soon. The earlier you test, the lower your hCG levels will be. If you get an unclear result, test again a day or two later. As the hCG increases, a really positive test will get darker and darker.
- Use a more sensitive test. Different test types and brands have different hCG thresholds that must be met in order for them to indicate a positive result. Therefore, cheap tests that you can order online are more reliable than digital tests if tested early. Note that the downside of testing early is that you are more likely to be able to determine a chemical pregnancy. These very early miscarriages are quite common. They are mostly not a sign of a deeper fertility problem, and before there were highly sensitive pregnancy tests, women certainly often had chemical pregnancies without even realizing it.
- Don’t take in excessive fluids. If you drank a lot of water or urinated very often, your urine may be too dilute for a correct reading to be possible. It’s best to hold your urine for two to three hours to make sure it’s not overly diluted. The first morning urine is usually more concentrated than urine at any other time of the day.
What does it mean when you see a colorless line?
On an immersion test, a positive pregnancy result consists of two lines of the same color. If the second line is very pale and completely colorless, it could just be an indentation line.
We mentioned these indentation lines earlier in the test descriptions, do you remember? Just as ink can accidentally get on the feed line, sometimes the feed line itself can be barely visible. If your second line appears gray or colorless, it is likely a indent line and the pregnancy test is actually not positive.
By Lindsay Meisel | Jun 6, 2018
Tags: evaporation line, fertility, pregnancy, pregnancy, pregnancy tests, pregnant, getting pregnant, pregnancy, pregnancy test, trying to conceive, trying to conceive, evaporation line
Thanks for visiting we hope our article Positive pregnancy test or evaporation line?
, we invite you to share the article on Facebook, twitter and whatsapp with the hashtag ☑️ #Positive #pregnancy #test #evaporation #line ☑️!