Thanks for your question. The tests performed for STD symptoms are quite simple and nearly painless. Various methods are there by which STDs can be tested. Some are done through blood while others through urine sample. These tests do not show a positive result in a very short time of exposure like a week or less. Any disease require sometime to grow and multiply in the body of a host and show specific symptoms, called its incubation period. When the growth reaches certain level then only it comes positive in tests. There are many STDs like syphilis, Chlamydia, gonorrhoea, herpes, HIV/AIDS, hepatitis, HPV (Human Papilloma Virus), etc.
Test for Chlamydia and gonorrhoea is done through both swab (fluids from urethra, cervix and rectum) and urine sample. Test for syphilis is done by dark field microscopy at the affected area of syphilis sore. Though it can be done through blood but the results are not accurate. Swab from herpes sores (which looks like pimples) is taken for testing but the result is not very accurate after 48 hours of herpes sore outbreak. This must be done as quickly as possible. Three tests via blood for Hepatitis B are performed. One test detects the virus and the other two detects the antibodies made by the body against this virus. HPV test is done by taking swab from cervix and is only for women to detect cervix cancer.HIV test can be performed both by blood and swab. Blood sample gives result in a long time while swab taken from saliva gives a quicker result. But relying entirely on saliva test is just not done. It can give u hint whether you are carrying the virus or not but a blood test gives more accurate result. Good luck for your test.