How to Tell the Deviation Between a Positive Pregnancy Test & An Evap Line
By Lindsay Meisel
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Medically reviewed by Rachel Liberto, RN on Baronial 26, 2022
Oh, the dreaded confusion betwixt a positive pregnancy test and an evaporation line. If you’ve e’er tossed a negative pregnancy exam in the trash, only to dig it out hours later and exist shocked by that 2nd line, you know what nosotros’re talking about. In virtually cases, it’s not a true positive, simply rather a very fell and disruptive phenomenon called an evap line.
You may already know when to take a pregnancy test and how to avert a false negative pregnancy test. But do you know how to ensure the second line is a true positive? To understand why evap lines happen and how to avoid them, let’s kickoff go over the anatomy of a pregnancy test.
How do pregnancy tests work?
There are three types of home pregnancy tests (HPT): mid-stream tests, dip tests, and dropper tests.
- Mid-stream tests: These are held in the stream of urine for a few seconds and and then set aside for a few minutes to await for the results.
- Dip tests: Pee in a cup, and so dip the exam (usually in the class of a strip) into the cup.
- Dropper tests: With these types of test, urine is dropped inside the testing well using a dropper that has collected fresh urine from a cup.
For all of these tests, the most important step is reading the instructions first. Different tests comprise different instructions, and sometimes, a single box of tests contains unlike types, where the instructions are slightly different for each examination. Exist sure to read the instructions thoroughly and so you don’t waste your pee!
When the await time has passed, you expect into the results window to decide whether the exam is positive or negative. Positive tests deport a plus sign, two lines, or an explicit bulletin like “pregnant” or “yes.”
The tests that show ii line results have two hidden “indent” lines where the ink pools: one for the control line, and ane for a potential positive result. Equally the ink moves across the result window, information technology collects in these one or both of these indents.
What is an evap line and how is it different from a positive pregnancy examination?
An evap line (evaporation line) is a faint line that appears afterward a negative exam has dried. Because tests are typically meant to be read 3 to five minutes after they are taken, the tests are still damp at the time they are read. After this time frame passes, the urine in the test dries.
As the ink makes its way across the screen, the event is displayed. Sometimes, as the ink moves across the screen, a little fleck of ink will accidentally get caught in the indent line. As the exam dries and the urine evaporates, this caught ink is pulled to the surface and becomes darker.
This is why the most important rule for getting a truthful positive pregnancy exam is:
do non read them later the allotted fourth dimension!
The results are only authentic in the time frame specified in the instructions.
How to distinguish a faint positive pregnancy exam from an evap
Okay, then now you know how to spot a false positive pregnancy test. Merely what nearly when you run into a faint line on a pregnancy test within the fourth dimension frame allotted by the test? How practise you know it’southward actually a positive pregnancy test?
- Don’t test as well early. The before you exam, the lowest your hCG levels volition be. If you have a real squinter, examination once again in a day or 2. As hCG rises, a true positive test will darken.
- Accept a more sensitive test. Unlike test types and brands have different hCG thresholds in guild to brandish a positive consequence. (Our guide to the best pregnancy tests includes hCG thresholds by test brand.) Keep in mind that the downside of testing early on is that yous are more likely to notice out if you take a chemical pregnancy. These very early on miscarriages are quite common, they usually do not signify whatsoever kind of underlying fertility problem, and before the advent of highly sensitive pregnancy tests, women might take had chemic pregnancies without fifty-fifty realizing it.
- Don’t over-hydrate. If you take been drinking a lot of water and/or urinating frequently, your urine may be too dilute for an authentic reading. It’s best to avoid drinking fluids for two or three hours to ensure that your urine is not too diluted. First morning urine is commonly more than full-bodied than urine from random hours during the twenty-four hour period.
What does information technology mean if there is a line with no color?
On a dip exam, a positive pregnancy result is two lines of the same color. If there is a very faint second line with no color at all, information technology’s possible for it to be an indent line.
Remember the word above most indent lines and the way pregnancy tests work? In the aforementioned way that ink may accidentally pool in the indent line, the indent line itself may sometimes go barely visible. If your second line appears gray or colorless, it is probably an indent and not a true positive pregnancy test.
By Lindsay Meisel