Advice Please First Potential Positive

I think I got my very first positive test this morning, but it was a vvfl. I'm going to retest with a pink dye tomorrow morning. I went and looked at the old test when I got home from work 8 hours later and saw a thin blue line plain as day. I know the test is not valid after that long, but I was curious. Is it possible to get an evap line that's blue like it was without the original result being a positive?