I'll try to explain this as simply as I can. I'm going abroad to teach English, most if not all foreign countries require a medical check (including an STD blood test) for a work VISA. No problem, I'm clean right now, was tested in January for just about everything. I'm reading in several forums concerning working overseas that a STD blood test can detect the presence of an STD years after you are cured. I'm concerned because I did have chlamydia about 1 year ago and I wonder if this would show up on a blood test? I'm assuming maybe antibodies might show up? I also had what my doctor suspected was a Chancroid but turned out to be a boil and it tested positive for staph bacteria.