The STD community gets so many questions about when to test, how to test, where to test. Here is a basic list, and all can be done by your regular doctor, or at an STD or GUM clinic.
Gonorrhea, chlamydia and NGU/NSU (men only):
* This testing is done by urine or swabbing the vagina or the urethra in men. This can be done at about a week past the possible exposure. Some countries are still doing blood testing for gonorrhea and chlamydia, but if you can get a urine or swab test, you should do that instead - its far more accurate.
* This is a blood test, and is usually accurate by about 6 weeks, though it may take longer in rare cases. The 2 most common are the RPR (rapid plasma reagin ) and VDRL (Venereal Disease Research Laboratory test). If this comes back positive, or "reactive", then a confirmatory test must be done. (A negative test will most likely read as "non-reactive".)
Confirmation tests could be either an FTA-ABS (Fluorescent treponemal antibody-absorption) test, TPHA and MHA-TP (Treponema pallidum hemagglutination assays), TP-PA (Treponema pallidum particle agglutination assay).
There are others, but those are the most common. If you have a chancre (sore), they can culture it, but that isn't done as frequently as it used to be.
*This can be a blood test, a finger stick or oral swab. The blood test will take around a week to come back, and the finger stick and oral swabs take 20 minutes to give results. All of those tests are the ELISA. If the ELISA is positive, a confirmatory Western Blot must be done, and that is a blood test.
All can take up to 3 months to be positive, but many will test positive before that. By the end of the first month, 90% will be positive if infected.
There are other tests, but you should see the HIV Prevention forum for more info on other testing - http://www.medhelp.org/forums/show/79 . Keep in mind that most people do not need other testing.
* Viral culture - this is a swab of the fluid within a blister. You should make sure that your doctor is ordering a type specific viral culture (see the herpes health page for more into on this - http://www.medhelp.org/health_pages/list?cid=84 ) These have a high false negative rate, so unless you have a positive test, you will need follow up testing if you have symptoms that might be herpes. Its is best to culture a new sore within 24-48 hours to insure the highest accuracy rates.
* Type specific IgG blood test - This will tell you if you have type 1, type 2 or both. (See the herpes health page listed above). It can not tell you where you have the infection (mouth or genitals), but can tell you if you have either. This can take up to 4 months to be accurate, but many will test positive long before.
See the herpes forum - http://www.medhelp.org/forums/show/195 for more info on herpes test results. There are other herpes blood tests, but most don't need them. See the herpes health page or the herpes forum if you are having difficulty getting consistent test results.
A note about the IgM test - this test is wrong at least as often as it is right, so it shouldn't be offered to you or drawn for you. If you get a positive IgM, please disregard it, as it is not enough by itself for a conclusive diagnosis.
*There are 3 types of hepatitis viruses - A, B, and C, and testing is done by a blood test.
Hepatitis B, the most commonly sexually transmitted of the hepatitis viruses, will be accurate by 9 weeks.
Hepatitis A is rarely sexually transmitted, as it is found in feces.
Hepatitis C is found in blood, and is also rarely sexually transmitted.
For more information on these, please see the appropriate hepatitis forums.
There are vaccines for hep a and b, and you might consider talking to your doctor about these.
For more info on stds, please post on the STD forum - http://www.medhelp.org/forums/show/98 - and not as a comment here.