The time it takes from infection to illness for each STD is different, from days to several weeks. Most STDs show no symptoms at all. Talk to a health care provider to find out what is right for you.
You can be exposed to STDs through skin contact (herpes, syphilis, HPV) or by exchanging body fluids like semen and vaginal fluid (chlamydia, gonorrhea, hepatitis B, and possibly hepatitis C) or by fecal matter (hepatitis A). Condoms work very well at preventing most of these exposures. If you think you have STD symptoms, get tested right away. If someone you have had sex with recently told you they were infected or if someone from Public Health called you about your sex partner testing positive, get tested right away. A health care provider may treat you before test results are back if your partner already tested positive for an STD.
Exposure to HIV is only possible by exchange of body fluids like blood, semen, vaginal fluid, and breast milk. No matter what kind of HIV test you get, there is a short period of time right after infection when the tests won't be able to detect signs of HIV, even if you are infected. This is called a "window period." If you get tested too soon (during the window period), your results may be wrong. How long you must wait depends on the type of test you take. Talk to your doctor.
NOTE: if you think you had an exposure to HIV, ask about PEP (Post Exposure Prophylaxis). Getting PEP within 72 hours of exposure can prevent HIV from establishing itself in your body.
For RNA or 4th generation antigen test:
These tests can usually detect HIV within 2 weeks after the infection. RNA/4th generation test are not available for in home use. It is important to see your doctor or health care provider as quickly as you can if you think you have been exposed to HIV. Starting treatment very soon after infection can help one’s health. If you think you may have been infected, get tested right away. This is particularly important if you think you have symptoms that might come from acute HIV (fever, fatigue, sore throat, muscle aching, rash).
For antibody testing in a clinic setting:
It's best to test three to four weeks after a possible exposure and again at three to six months.
For antibody testing using a home testing kit:
Home HIV test kits can give accurate results three months after infection. If a home test is positive, go to your doctor or a clinic right away for second test to confirm the result.