What is the most accurate test to find Chlamydia in men?

I have a cousin that was tested positive with chlamydia, she has been treated for it. She told her fiance when she was positive with it and must have gotten it from her previous relationship from her ex. and he got tested as well. So, his test came back negative for some reason. I know for a fact that he is faithful to her and she is to him because I am always around them and they are a couple that likes to be 100% with each other on everything no matter what. He did say that they did a swab test on him when he was tested for the STD. I am hearing that a swab test is not that accurate. She called her local health department and asked what is the most accurate test to have done and the nurse told her a urine speciman because it is more accurate and can detect all bacteria. Is it true that the urine test is more accurate than the swab test? Please..... I need advice I want to help my cousin and her fiance out here so that he can get cleaned. PLEASE NO ILLITERATE RESPONSES.