Pregnant or evaporation line?

You can't trust it. Blue dye tests tend to evap like that. Get a pink dye test.

Depends on how close to the time frame it showed up. I've read that even though it recommends viewing the results within 5-10 minutes that technically the test can't fully dry until about 20 minutes. An evap means that the urine has evaporated and the test has completely dried therefore making it invalid. If you are usually regular I'd say being late 15 days is indicative of something and you should go into a doctors office or planned parenthood for test, or maybe a blood test. Also, I prefer the pink dye tests, I've had better luck with those. Good luck! 

I think its positive but i swear by the dollar tree and walmart tests, they are very easy to read and at 15dpo you should be able to get a very clead positive with them and you can buy a few so that you dont have to worry that 1 was a fluke. Good luck!

Take a dollar store .88 test

Definitely a positive!!