Clearblue Pregnancy Test Faint Line: Blue Dye Problems
Clearblue tests use blue dye which can be tricky to read. Learn how to interpret faint or questionable lines.
The blue dye challenge
Clearblue uses blue dye, which is notorious for showing evaporation lines that look like faint positives. Many women in the TTC community specifically avoid blue dye tests for this reason.
Clearblue evap lines
Blue dye evap lines appear as a faint blue/gray shadow in the test window, usually after the reading time has passed. They can look convincingly like a positive, which causes a lot of confusion.
How to read Clearblue correctly
Read your result within 3 minutes (for Rapid Detection) or 2 minutes (for Digital). After that, the result is no longer valid. A true positive should be clearly blue—if you're squinting, it's probably an evap.
Clearblue Digital vs line tests
Clearblue Digital eliminates interpretation—it says 'Pregnant' or 'Not Pregnant.' However, it requires higher hCG levels (about 50 mIU/mL) so it may show negative when a line test shows faint positive.
Our recommendation
If you see a faint line on Clearblue, confirm with a pink dye test (like First Response). Our scanner can help analyze your Clearblue photo, but pink dye tests are generally easier to read definitively.
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