How faint can a pregnancy test line be

• A faint line on an at-home pregnancy test can mean you're in the earlier stages of pregnancy. 
• But, it can also mean the test wasn't taken properly, so its important to follow instructions. 
• If you get a faint line, start taking a prenatal vitamin and schedule a doctor's appointment. 

Understanding the results of an at-home pregnancy can feel surprisingly complicated at times. A pregnancy test measures the presence of the hormone human chorionic gonadotropin, or hCG, which is produced by an embryo. Though not as accurate as a pregnancy test at the doctors, an at-home pregnancy test can measure hCG levels with 97 to 99 percent accuracy. 

Pregnancy tests with blue or pink dye typically show one line if the result is negative and two if hCG is detected, meaning the result is positive. If you get any type of second line, even a faint one, you are pregnant, says Jennifer Lincoln, MD, an obstetrician in Oregon. "A line is a line, whether faint or dark. Any line means pregnant," she says. 

Here is what to do if you get a faint line on your pregnancy test at home according to an expert. 

What does a second, very faint line on a pregnancy test mean?

If you take a pregnancy test and a faintly colored second line appears, it usually means you are pregnant.  Here's why you could be getting a faint line:

It's early in your pregnancy. If you take a pregnancy test in the days immediately before or after a missed period, the test will only detect small amounts of hCG, which can show up as a faint line. Most pregnancy tests on the market only work properly if you take them a week or more after missing your period, says Cara Delaney, MD, a gynecologist and instructor at the Boston University School of Medicine. 

You have a chemical pregnancy. A chemical pregnancy is a type of miscarriage that happens very early on in pregnancy. It can cause a false positive result or a faint line on a pregnancy test because the brief pregnancy produces a small amount of hCG in your body.

You made a mistake in taking the test. "If you wait too long to read the test it can dry and leave a line that can be misinterpreted as a positive test," says Lincoln. Most pregnancy tests include instructions to read the results around three to five minutes after testing.

How long after a faint positive should I test again?

Lincoln says that if you get a faint line on your test and it concerns you, test again in the coming days. "It's most accurate to wait until the day of when you'd expect your period to come, but with the sensitivity of our tests it is OK to start testing a few days prior."

If an at-home pregnancy test is positive, "the majority of people don't need a blood pregnancy test to confirm they are pregnant. And in fact, our[doctors'] urine tests are exactly the same as the ones you can buy yourself so no need to come in for those either," says Lincoln. 

There are some circumstances where a blood test might be needed: "If your healthcare provider is concerned about an ectopic pregnancy or miscarriage, or you are undergoing fertility treatments, a blood test may be recommended, but other than that they aren't usually needed."

Insider's takeaway 

If you take an at-home pregnancy test correctly and see a faint line, it either means you are pregnant or have recently been pregnant and miscarried. 

The best time to test for a pregnancy is the day you would expect your period to come.

A faint line on a home pregnancy test may leave you wondering whether you're pregnant or not – but if it's even faintly positive, you're most likely pregnant. The test looks for a hormone called human Chorionic Gonadotropin (hCG) in your urine. Your body starts producing hCG right after implantation, but your levels may not be high enough for a home pregnancy test to measure if you take it too soon. If you get an unclear result like a faint line, take another pregnancy test in a few days, or ask your healthcare provider for a blood test to detect pregnancy.

What does a positive pregnancy test look like?

A positive pregnancy test result will look different depending on the kind of test you use. All of them test your urine on a prepared strip. For some tests, you urinate directly onto the strip. For others, you pee in a cup and then either dip the test strip into the cup or use a dropper to place a sample of your urine on the test strip.

Results from a home pregnancy test may look like:

• A plus or minus sign
• One line or two lines (with two lines indicating pregnancy)
• A pink line
• A blue line
• The words "pregnant" or "not pregnant"
• The words "yes" or "no"

Read the package instructions carefully. They'll tell you exactly how to do the test and how to read the results. Most tests have a control line where you can check to see that you did the test correctly. If that control line is blank, then the test didn't work, and you'll want to do another one.

What does a faint line on a pregnancy test look like?

The line on your pregnancy test may be difficult to read because it's barely visible. A line that's supposed to be red may appear light pink, for example, and a line that should look blue if positive will be very light blue. Digital results will appear in words, so there are no faint lines to wonder about. They will read "yes" or "no," or "pregnant" or "not pregnant."

In an effort to read very early test results, or test results that are unclear, some women turn to pregnancy test tweaking. This involves taking a photo of your home pregnancy test and editing it to see if you can detect the line that indicates pregnancy. There's no proof that this is reliable, but some women are giving it a try.

What does a faint line on a pregnancy test mean?

A faint line on a pregnancy test probably means that it's very early in your pregnancy. Even a faint positive pregnancy test indicates that you have some of the pregnancy hormone human Chorionic Gonadotropin (hCG) in your system.

Your body starts producing hCG right after implantation. If you have a typical 28-day menstrual cycle, hCG may be detectable in your urine 12 to 15 days after ovulation if you're pregnant. The levels of hCG are very low at first and then they rise quickly, doubling every three days in early pregnancy. That's why you might have a faintly positive result at first and one that's crystal clear a few days later.

Here's why you might see a faint line on your pregnancy test results:

• Testing too early
• Using an expired test
• Not checking the results in time. The directions will tell you to check the results within a certain amount of time (usually a few minutes). That's because the results are accurate when the urine is still wet. Once it dries, urine may leave a faint line where it evaporated – an "evap line." Unlike positive result lines, which are usually dark or bright, an evap line will be colorless.
• Very diluted urine. To minimize the possibility of this happening, take your test first thing in the morning, when your urine will be the most concentrated.

Of course, if it's really too early, you may not even see a faint line. Instead you might get a negative result because your hCG levels aren't high enough to be detected. The earlier you test, the higher the chances that you'll get a false negative test even if you're pregnant.

What to do if you see a faint line on a pregnancy test

If you see a faint line, the best thing to do is wait a few more days and take a home pregnancy test again. By then your levels of hCG should rise enough to give you a clearly visible result.

Another option is to ask your healthcare provider to confirm that you're pregnant with a blood test, which can usually detect pregnancy a few days earlier than a home pregnancy test. (HCG can be detected in the blood about 11 days after conception and in urine about 12 to 15 days after conception.)

If you saw a faint positive result and retested in a few days with a negative result (or you got your period after testing positive), you may have experienced a chemical pregnancy or early miscarriage. A chemical pregnancy means the egg was fertilized but didn't completely implant. So your body may have produced a little hCG but then stopped when the embryo stopped developing.

What can cause a false positive pregnancy test?

It's pretty rare, but there are reasons you might have hCG in your body and not be pregnant, giving you a false positive result on your pregnancy test:  

• An early pregnancy loss. This might be from a chemical pregnancy or an ectopic pregnancy. A chemical pregnancy happens if the fertilized egg doesn't implant. An ectopic pregnancy happens if the fertilized egg implants someplace other than the uterus (usually in a fallopian tube).  If you continue to get a faint line, talk with your doctor to figure out what's going on.
• Fertility drugs and some other medications. Medications that are used in fertility treatment may contain traces of hCG that remain in your system for a week or more. Most medications, including birth control medication, won't affect the accuracy of your pregnancy test.
• A recent birth, miscarriage, or abortion. It can take weeks for hCG to completely leave your system after a pregnancy.
• Perimenopause or menopause. Higher levels of luteinizing hormone from perimenopause or menopause could possibly result in a positive pregnancy test.
• Certain medical conditions. Rarely an ovarian cyst and some cancers can cause a false positive pregnancy test result.

Learn more:

• How to get pregnant
• Can you get pregnant on or right after your period?
• Pregnancy symptoms: 11 early signs of pregnancy
• Am I pregnant? Quiz

How faint does a line have to be to be positive?

How long after a faint positive should I test again?

Does faint line mean low hCG?

How do you tell if it's a faint positive or evaporation line?