What Do Two White Lines Mean On A Pregnancy Test?

If you're wondering whether or not you might be pregnant, a home pregnancy test can be a fast way to provide answers. These tests rely on a chemical reaction to detect human chorionic gonadotropin (hCG), a hormone that increases rapidly during the early weeks of a pregnancy. While some tests provide a digital message that says "pregnant" or "not pregnant," many tests reveal lines as the urine sample is absorbed. In this case, two colored lines are a clear indication of pregnancy, and just one colored line means not pregnant. Unfortunately, the results aren't always this clear, and you may see two white lines.

Since the lines are supposed to have at least a tinge of color, take a new test if you get two white lines. Similar to getting zero lines, white lines are an indication that the test isn't working correctly. Storing your tests in high heat or humidity can compromise a test's sensitivity. If the pregnancy test is expired, it may produce faint lines that look like white lines, and accurate results are no longer guaranteed.

Test instructions are also specific about when to read the results. If you check a test too late, you might see a white line that's an evaporation line. This line is the test strip drying, not an indication of pregnancy. Another source of a white line is known as an indent line. This is actually part of the test, even before it's used. Besides a lack of color, this line might look like a divot in the strip.

Ensuring you're following the instructions can help to ensure you get accurate results and avoid those dreaded white lines. One of these best practices is to test in the morning so your urine is more highly concentrated, since a diluted sample could skew the result. Although waiting can be difficult, if you test too early, you may not get accurate results since enough hCG hasn't built up in your urine. 

Although some tests can be taken days ahead of an expected period, their efficacy increases over time. For instance, First Response notes that accuracy is 76% five days ahead of a period and more than 99% just two days later. Early testing can also lead to a positive line looking very pale — one that you may think is a white or slightly colored line. If you see a faint line, you may want to wait a couple of days, retest, and see if the line is more visible on the second test.

Although symptoms like a missed period, fatigue, and spotting could indicate a pregnancy, a test is the only definitive way to know for sure. If a home pregnancy test isn't providing clarity, a visit to your healthcare provider can offer guidance. Depending on the situation, medical professionals use both urine and blood tests. If you are pregnant, they can also advise you on prenatal care and answer any immediate questions or concerns.