Health Tips

Whether a pregnancy test turns out positive or negative, most women would agree that getting one can be one of the most nerve-wracking experiences they have or will be going through.

And that’s normal.

Because let’s face it, things can get a little confusing to understand and correctly interpret what the lines on the test actually mean.

How Does Home Pregnancy Test Work?

In general, an at-home pregnancy test is a simple way to find out if you’re pregnant before seeing a doctor. If you are not sure how to use one, here’s an Infographic on How To Use Home Pregnancy Test.

This test works by detecting the levels of human chorionic gonadotropin (hCG) levels during the first trimester of pregnancy, which is a hormone the body produces during pregnancy.

The test process itself is easy as it only requires users to urinate on the test stick and checking the results after a few minutes. But the results often can be confusing. 

Some pregnancy test involves two lines: a control line and a test line. The control line should appear on every test (an indication that the pregnancy test is valid), but the test line appears only if there are some levels of hCG detected in your urine.

1. If your pregnancy test result only reveals one line (the control line), it often means you’re not pregnant.

2. If the test results reveal the control line and the test line, this may indicate a pregnancy, but it doesn’t necessarily have to be that way. The second line could be an evaporation line.

What is an Evaporation Line?

An evaporation line (evap line) is a slight streak that appears after a negative test has dried.

Basically pregnancy tests are meant to be read three to five minutes after they are taken when the tests are still damp at the time of reading.

This does not indicate that a woman is pregnant as the lines often occur when a person has checked the result too late or taken the test incorrectly.

When an evaporation line appears, it is best to take another test for an accurate result.

How to tell the difference: Faint positive test vs. Evaporation line

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

• More than 10 minutes have passed since taking the test.

• The mark is faint and colorless, and it resembles a water spot.

• The mark has no visible dye in it.

If the control line on the test does not change color, this means that the test is not valid and you should repeat the test with a new pregnancy test kit.

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

• You notice a visible dye in the line, even if the color is faint

• The line appears within the period specified on the instructions, usually between 3-5 minutes.

• A woman has taken a regular test at least 14 days after ovulation

• A woman has missed her period.

Evaporation lines are usually avoidable if you follow the instructions on the test packaging. A simple way to help ensure accuracy is to take two tests.

This is why the most important rule for getting a true positive pregnancy test is:

“Do not read them after the allotted time!”

If you are still unsure of the interpretation of the results, talk to your doctor and get your blood tested.

Download our Doc2Us app from Google Play Store or Apple Store and chat with a doctor now.

References:

1. Ernst, H. (2019). Evaporation line on a pregnancy test: What to know. [online] Medical News Today. Available at: https://www.medicalnewstoday.com/articles/322633.php.

2. Liberto, R. (2019). The Difference Between a Positive Pregnancy Test & An Evap Line. [online] Ava. Available at: https://www.avawomen.com/avaworld/positive-pregnancy-tests-evap/.

3. Weatherspoon, D. (2018). Evaporation Line Pregnancy Test: Positive or Negative?. [online] Healthline. Available at: https://www.healthline.com/health/pregnancy/evaporation-line-pregnancy-test#next-steps.

Image credits:

1. https://amp.flo.health/uploads/media/sulu-1230x-inset/04/1214-Woman%20holding%20a%20pregnancy%20test.jpg?v=1-0&inline=1

2. https://cf-images.us-east-1.prod.boltdns.net/v1/static/5966354423001/53df024f-c2ac-461a-bd6e-c4602e0c8c16/9e2dab11-0f21-4873-9dae-a3f23fb32dab/1280x720/match/image.jpg

3. https://usercontent1.hubstatic.com/14004116_f520.jpg

4. https://malcomabortionclinic.co.za/wp-content/uploads/2019/05/How-to-stop-unwanted-pregnancy-1.jpg

Written by

Dr. Jeanrette J. Nierras