Hi there, I am extremely sorry for not getting back to you sooner. By shadow, do you mean that you could see where the test line would be? Sometimes under certain light you can see where the test line is positioned, however as long as there is no red/pinkish line then it is just where the test line has been sprayed onto the test strip. The fact that your possible exposure was 4 months ago - I would say that if you were to have been infected a test line would most likely not be faint and would be visible given the time since your exposure. A negative result at 4 months is conclusive and you do not need to retest. Your anxiety is completely normal but given that you have tested negative outside of the window period, I would suggest that you try to move on and put this behind you. I hope I have been able to ease your worry, but if you have anymore questions please feel free to leave them below. Thank you very much for your patience. All the best, the BioSure team.

Would the positive line also be very visible after 4/5 months?