Community post

Blue dye tests are notorious for bad evap lines and false positives. Before I knew better I got some blue dye cheapies and got multiple faint, but very clear BFP's, within the timeframe for the test - even though I didn't think I could be pregnant and sure enough, testing the very same urine with a better test came up BFN. In theory there shouldn't be any difference, but googling found lots of other people who've had the same problem (including one woman who did a whole gallery of how bad the blue dye tests can be, her boyfriend was pregnant according to blue dye tests!). I personally wouldn't trust a blue dye test now, but your mileage may vary!

I bought some blue dye tests by accident and have had 3 false positives with them. All three had positive results that came up within the time frame. I used the same urine with a FRER and got a BFN. I will never buy them again.