STDs are caused by bacteria, viruses, or parasites. Common STDs include chlamydia, gonorrhea, genital herpes, HIV, and HPV (human papillomavirus) infection. STD testing can help you get diagnosed and treated so you may avoid serious complications. STD testing refers to several different methods to detect an infection, such as blood tests, vaginal discharge tests, stool test, and laparoscopy. Each type …