Has nothing to do with being contagious. Slight blood in the urine usually indicates an urinary infection which may need antibiotics. They are looking for both easily contagious things but most importantly medical conditions that are expensive to treat.Don't be worried friend. I had blood in my urine too( +1). I was worried but the doctor said everything is ok. 16 days after my AOR I got MEP and i am at IP1 stage now. You will pass your medical. It isn't contagious