The amount of time it takes your body to test positive for an STI depends on the type of STI. STIs like gonorrhea, chlamydia, and trichomoniasis can show up in a few days after exposure while infections like syphilis, herpes or HIV, depending on the test, can take at least 7 days and often longer. Gonorrhea, chlamydia and trichomoniasis are detected with a swab or urine test that measures the presence of the actual germ. Syphilis and herpes can be detected from the fluid in a sore when there is a sore present. There are also blood tests for syphilis and herpes. HIV can be detected with a blood or oral fluid test that measures the body’s immune reaction to the germ through the creation of antibodies. HIV can also be detected by testing for the HIV virus in the blood BEFORE you have even created antibodies.