A blood test involves taking samples of your blood from a vein in your arm and sending those samples to a lab for screening. Blood tests can screen for common STDs like HIV, the potentially deadly virus that causes AIDs; HSV, the virus that causes herpes; hepatitis B, a virus that inflames the liver; and potentially deadly syphilis. Urine tests are not as always as accurate as blood tests. They are, however, a way to screen for diseases like HIV, or gonorrhea, which can cause infertility or even death. A physical exam is another way in which a doctor can check for STDs. Because some STDs involve outbreaks, a visual exam may be all that is needed for diagnosis. STDs like genital herpes, syphilis, pubic lice, or genital warts, which are caused by HPV, can be seen with the naked eye. However, a follow-up test is usually ordered to confirm the diagnosis. For women, the best confirmation for many STDs is a swab test, which usually involves taking a sample of the cells in the cervix. A cervical swab can test for gonorrhea; Chlamydia, which can cause infertility; and the bacterial infection trichomoniasis. A pap smear, which is a similar procedure, can test for HPV, the virus that causes genital warts and cervical cancer in women. STDs can be scary, but many are treatable