I had a faint positive pregnancy test then a negative

After getting a negative result on a home pregnancy test, it's fair to conclude that you're not pregnant. However, if you happen to glance back at the test later in the day, you may be surprised to see that a positive line has magically appeared. There are a few reasons why this can happen. However, in most cases, the originally reading of the test, "not pregnant," is typically the correct one.

What Are Evaporation Lines on a Pregnancy Test?

The instructions on most pregnancy tests will advise you to read the results within a certain window of time. This usually ranges between a couple of minutes up until 10 minutes later. If you see a positive result beyond this time frame, you may be left second-guessing the results.

However, the false-positive reading, in this case, is due to something called an evaporation line. Evaporation lines are not indicative of a true positive result.

Evaporation lines happen when the urine that was on the test area starts to dry. The chemical composition of the urine sample changes due to evaporation. As a result, the test may start to display a positive line. After the allotted time has passed, you should discard the pregnancy test to avoid confusion.

If you follow all of the instructions correctly, you may notice a thin, faint test line that appears within a few minutes. It can seem at first that the line is too faint to count, but after 10 minutes, it darkens. There are several possible explanations for this line:

• Chemical pregnancy: When implantation of a fertilized egg happens, hCG is produced, even though that egg may not be viable. Chemical pregnancies are the most common cause of early miscarriage. Without taking a pregnancy test, the miscarriage may easily be mistaken for a regular period.
• Lower sensitivity test:You might need a test with higher sensitivity levels so that you can get accurate results earlier in the pregnancy. Look for "early results" indicated on the test label.
• Too early in your cycle: If you test earlier than 10 to 12 days past ovulation, the hCG hormone may not be high enough to produce more than a very faint line. The best time to test is after your period is late, or 2 weeks after you ovulated.
• Too much fluid: You can dilute your urine sample if you are urinating too frequently or drinking too many liquids—this is why first-morning urine samples are recommended for pregnancy testing.

False Negative Results

While true false negative results are rare, there are multiple reasons why you could get a negative or faint result even if you are actually pregnant, such as not waiting long enough into your cycle to test or testing with diluted urine. Always use a sample from your first-morning urine (which is more likely to have higher concentrations of the pregnancy hormone, hCG).

If you are still unsure about pregnancy test results, wait a few days and test again. If you have any questions or concerns about whether or not you could be pregnant, consult with an OB/GYN.

A Word From Verywell

It can very stressful to see conflicting results on a pregnancy test, such as faint lines or evaporation lines. If you're unsure about your results, retest in a couple of days or talk to your doctor about a follow-up blood test for confirmation. Following the directions on your pregnancy test helps avoid the confusion or disappointment of a false positive.

Verywell Family uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.

By Robin Elise Weiss, PhD, MPH
Robin Elise Weiss, PhD, MPH is a professor, author, childbirth and postpartum educator, certified doula, and lactation counselor.

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When you are trying to conceive, you may have many questions. Receiving a faint positive pregnancy test result one day, and then a negative pregnancy test result the next can make the conception process much more confusing. You may also receive a negative pregnancy test and then a positive pregnancy test several hours later. Confusing, right?

This article, “What Causes A Faint Positive Pregnancy Test then Negative the Next Day”, discusses the 5 reasons why your pregnancy test results may change over night, and what is considered a positive pregnancy test result.

In this article:

• What Does A Positive Pregnancy Test Result Look Like?
• What Causes a Faint Positive Pregnancy Test?
• 5 Reasons Why A Pregnancy Test Result May Change From Positive to Negative Overnight

What Does A Positive Pregnancy Test Result Look Like?

How a positive pregnancy test result looks varies, depending on what type of pregnancy test you use. You may use a pink dye test, blue dye test or digital test- and then different tests of those types vary with how they show their pregnancy test results.

A positive pregnancy test result may look like:

• Two pink lines on a pink dye test
• Two blue lines on a blue dye test
• The word “pregnant” on a digital test
• The word “yes” on a digital test
• A plus sign on a pink or blue dye test

It is important the ensure that you follow the test instructions carefully, so the test is performed and the pregnancy test results are read correctly

What Causes a Faint Positive Pregnancy Test?

A faint positive pregnancy test is a pregnancy test where the test line is barely visible. The colours of the test line may appear a lighter shade, for example a line that should be dark pink may be very light pink, and a line that should be a vivid blue may appear as a very light blue.

It is important that you ensure that the evaporation line is not mistaken for positive test results.

5 Reasons Why A Pregnancy Test Result May Change From Positive to Negative Overnight

When you are trying to conceive, it can be disappointing and discouraging when the positive pregnancy test you receive becomes a negative result overnight- but what can cause this? We discuss the 5 reasons why a positive pregnancy test result may change to a negative result. If your pregnancy test result changed in 2 hours, we have an article about that too: Positive pregnancy Test Then Negative 2 Hours Later – 4 Reasons Why

1) Evaporation Line

Sometimes, a test that you believed was positive, may not have been positive at all. How can this be? Well, those pesky evaporation lines can wreak havoc when interpretting your pregnancy test results!

Blue dye pregnancy tests show evaporation lines: a very faint line which shows in the place of the test line, in the case of a negative test (otherwise, in the case of a positive pregnancy test result, it will become much darker in colour). So, if you took a blue dye pregnancy test the day before, and misinterpretted the evaporation line on the pregnancy test for a faint positive result (false positive), it may explain why your result has “changed” to negative overnight!

To avoid this issue, it is recommended that you use pink dye pregnancy tests.

2) Chemical Pregnancy

If you received a faint positive result on a home pregnancy test, and then received negative results the day after, it may be a sign of a chemical pregnancy (or early pregnancy loss that occurs before 5 weeks of pregnancy).

Symptoms of a very early miscarriage (before 5 weeks of pregnancy) include:

• A period with heavier flow than normal
• Low hCG levels
• Lack of (your usual) pregnancy symptoms (including morning sickness, fatigue and breast tenderness)

Early miscarriages often occur due to chromosonal abnormalities. Other causes of chemical pregnancies include:

• Genetic abnormalities
• Failed implantation
• Low BMI
• Hormone imbalance

3) Time of Day

Sometimes the time of day can affect your pregnancy test results. If you take your pregnancy test in the morning- you are more likely to get a faint positive pregnancy test, as the human chorionic gonadotropin (hCG) levels tend to be higher in the morning, as your urine is more concentrated. If you took a pregnancy test in the morning and received a faint positive result, and then took a pregnancy test at night and received a negative, you should try and take a pregnancy test again in the morning

4) You Are Very Early In Your Pregnancy

If you are receiving mixed pregnancy test results, it may just be that you are too early in your pregnancy to receive accurate results.

You can take most pregnancy tests from the first day of your missed period. If you are unsure when your period is due, you should take a pregnancy test at least 3 weeks (or 21 days) after you had unprotected sex.

5) It Was A False Positive Result

Sometimes, pregnancy tests can fail and provide inaccurate results. The most often malfunction in a pregnancy test is that the control line on a pregnancy test will not show.

Pregnancy tests rarely malfunction if they are from a reputable brand, such as clear blue.

Hi, I’m Louise- mum of one to a little boy called Mason.

I am the Digital Marketing and Admin Assistant for MyBump2Baby.

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Can a pregnancy test show a faint line and be negative?

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