Can evap lines have colour??

Natalie • Mama to a👦 7/18/17, 👼🏻 9/26/18, 👦 8/2/19, 👧🏻 7/29/2021, 🤰 due 8/5/2023
I took a blue dye test and test line is blue but I am skeptical. Is there a way to test if it is an evap? This was taken with FMU 10 DPO. Thanks for your advice!